ABCA1 p.Leu222Ala
| Predicted by SNAP2: | A: D (66%), C: D (63%), D: D (80%), E: D (80%), F: D (71%), G: D (80%), H: D (75%), I: D (63%), K: D (80%), M: N (53%), N: D (80%), P: D (91%), Q: D (75%), R: D (80%), S: D (71%), T: D (71%), V: N (66%), W: D (80%), Y: D (71%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: N, G: D, H: D, I: N, K: D, M: N, N: D, P: D, Q: D, R: D, S: D, T: D, V: N, W: D, Y: D, |
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[hide] Carboxyl terminus of apolipoprotein A-I (ApoA-I) i... J Biol Chem. 2011 Mar 11;286(10):7744-54. Epub 2011 Jan 5. Ohnsorg PM, Rohrer L, Perisa D, Kateifides A, Chroni A, Kardassis D, Zannis VI, von Eckardstein A
Carboxyl terminus of apolipoprotein A-I (ApoA-I) is necessary for the transport of lipid-free ApoA-I but not prelipidated ApoA-I particles through aortic endothelial cells.
J Biol Chem. 2011 Mar 11;286(10):7744-54. Epub 2011 Jan 5., [PMID:21209084]
Abstract [show]
High density lipoproteins (HDL) and apolipoprotein A-I (apoA-I) must leave the circulation and pass the endothelium to exert their atheroprotective actions in the arterial wall. We previously demonstrated that the transendothelial transport of apoA-I involves ATP-binding cassette transporter (ABC) A1 and re-secretion of lipidated particles. Transendothelial transport of HDL is modulated by ABCG1 and the scavenger receptor BI (SR-BI). We hypothesize that apoA-I transport is started by the ABCA1-mediated generation of a lipidated particle which is then transported by ABCA1-independent pathways. To test this hypothesis we analyzed the endothelial binding and transport properties of initially lipid-free as well as prelipidated apoA-I mutants. Lipid-free apoA-I mutants with a defective carboxyl-terminal domain showed an 80% decreased specific binding and 90% decreased specific transport by aortic endothelial cells. After prior cell-free lipidation of the mutants, the resulting HDL-like particles were transported through endothelial cells by an ABCG1- and SR-BI-dependent process. ApoA-I mutants with deletions of either the amino terminus or both the amino and carboxyl termini showed dramatic increases in nonspecific binding but no specific binding or transport. Prior cell-free lipidation did not rescue these anomalies. Our findings of stringent structure-function relationships underline the specificity of transendothelial apoA-I transport and suggest that lipidation of initially lipid-free apoA-I is necessary but not sufficient for specific transendothelial transport. Our data also support the model of a two-step process for the transendothelial transport of apoA-I in which apoA-I is initially lipidated by ABCA1 and then further processed by ABCA1-independent mechanisms.
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No. Sentence Comment
46 Generation of Adenoviruses Expressing ApoA-I(L218A/L219A/ V221A/L222A)-The apoA-I gene lacking the BglII restriction site (that is present at nucleotide positions 181 of the genomic sequence relative to the ATG codon of the gene) was cloned into the pcDNA3.1 vector to generate the pcDNA3.1- apoA-I(⌬BglII) plasmid as described (30).
X
ABCA1 p.Leu222Ala 21209084:46:64
status: NEWX
ABCA1 p.Leu222Ala 21209084:46:79
status: NEW47 This plasmid was used as a template to introduce the apoA-I(L218A/L219A/ V221A/L222A) mutations in apoA-I using the mutagenesis kit QuikChange XL (Stratagene) and the mutagenic primers.
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ABCA1 p.Leu222Ala 21209084:47:79
status: NEW56 The mutant protein was isolate from the culture medium of HTB-13 cells infected with the apoA-I(L218A/ L219A/V221A/L222A)-expressing adenovirus as described (22, 26).
X
ABCA1 p.Leu222Ala 21209084:56:115
status: NEW94 The two mutants with a defective carboxyl-terminal sequence, apoA-I(⌬185-243) and apoA-I(L218A/L219A/V221A/L222A), showed 50 and 80% decreases in total and specific endothelial binding, respectively (Fig. 1).
X
ABCA1 p.Leu222Ala 21209084:94:114
status: NEW103 The results are represented as means Ϯ S.D. (error bars) of at least three individual experiments. Transendothelial ApoA-I Transport Is a Two-step Process 7746 binant WT apoA-I, and apoA-I(⌬144-165) did not differ from each other whereas the apoA-I(⌬185-243) and apoA-I(L218A/ L219A/V221A/L222A) mutants showed strongly reduced total and specific cell association, and the apoA-I(⌬1-59) and apoA-I(⌬1-59/⌬185-243) mutants showed massively increased total cell association which could not be competed by WT apoA-I (data not shown).
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ABCA1 p.Leu222Ala 21209084:103:310
status: NEW109 In contrast, the specific transports of apoA-I(⌬185-243) and apoA-I(L218A/L219A/V221A/L222A) were decreased by 90%.
X
ABCA1 p.Leu222Ala 21209084:109:93
status: NEW112 Therefore, we compared the particle sizes of WT apoA-I and the dysfunctional apoA-I(L218A/L219A/V221A/L222A) mutant before and after transport through ECs (Fig. 3).
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ABCA1 p.Leu222Ala 21209084:112:102
status: NEWX
ABCA1 p.Leu222Ala 21209084:112:125
status: NEW114 By contrast, the comparison of the gel filtration profiles of the binding- and transport-defective apoA-I(L218A/ L219A/V221A/L222A) mutant before and after incubation with ECs did not reveal the occurrence of any new peak (Fig. 3B).
X
ABCA1 p.Leu222Ala 21209084:114:54
status: NEWX
ABCA1 p.Leu222Ala 21209084:114:125
status: NEW116 The larger sized fraction of apoA-I(L218A/L219A/V221A/L222A) has a higher elution volume than the fraction formed after transport of WT apoA-I and did not change after transport.
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ABCA1 p.Leu222Ala 21209084:116:54
status: NEW117 We therefore assume that this fraction represents lipid-free aggregates of apoA-I(L218A/ L219A/V221A/L222A).
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ABCA1 p.Leu222Ala 21209084:117:101
status: NEW138 Binding and Transport of Reconstituted HDL Containing WT ApoA-I or ApoA-I(L218A/L219A/V221A/L222A)-Next, we exploited the apoA-I(L218A/L219A/V221A/L222A) mutant with defects in ABCA1-mediated lipid efflux as well as specific endothelial binding and transport to test the hypothesis that transendothelial transport of lipid-free apoA-I occurs by a two-step mechanism in which apoA-I is first lipidated by ABCA1-dependent lipid efflux to then undergo ABCA1-independent transport through ECs.
X
ABCA1 p.Leu222Ala 21209084:138:92
status: NEWX
ABCA1 p.Leu222Ala 21209084:138:147
status: NEW139 We first lipidated WT apoA-I or apoA-I(L218A/L219A/V221A/L222A).
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ABCA1 p.Leu222Ala 21209084:139:44
status: NEWX
ABCA1 p.Leu222Ala 21209084:139:57
status: NEW141 Both WT apoA-I and apoA-I(L218A/L219A/V221A/L222A) formed particles that had a higher electrophoretic mobility than the respective lipid-free apolipoproteins.
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ABCA1 p.Leu222Ala 21209084:141:44
status: NEWX
ABCA1 p.Leu222Ala 21209084:141:135
status: NEW142 rHDL containing apoA-I(L218A/L219A/ V221A/L222A) were slightly less negatively charged than rHDL containing WT apoA-I (Fig. 6A).
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ABCA1 p.Leu222Ala 21209084:142:42
status: NEW143 In addition, the Sudan Black staining of the agarose gel clearly reveals the lipidation of both WT apoA-I and apoA-I(L218A/L219A/V221A/L222A).
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ABCA1 p.Leu222Ala 21209084:143:79
status: NEWX
ABCA1 p.Leu222Ala 21209084:143:135
status: NEW145 Electron microscopy revealed that both WT apoA-I and apoA-I(L218A/L219A/ V221A/L222A) formed discoidal particles (Fig. 6C).
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ABCA1 p.Leu222Ala 21209084:145:79
status: NEWX
ABCA1 p.Leu222Ala 21209084:145:171
status: NEW147 Neither the specific binding (Fig. 6D) nor the specific transport (Fig. 6E) differed between particles containing either WT apoA-I or the mutant apoA-I(L218A/ L219A/V221A/L222A).
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ABCA1 p.Leu222Ala 21209084:147:171
status: NEW148 Thus prelipidation can overcome the binding and transport defects of the dysfunctional apoA-I(L218A/L219A/V221A/L222A) mutant.
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ABCA1 p.Leu222Ala 21209084:148:112
status: NEW154 Particle size of WT apoA-I and apoA-I(L218A/L219A/V221A/L222A) before and after transport through ECs.
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ABCA1 p.Leu222Ala 21209084:154:56
status: NEW158 B, 125 I-apoA-I(L218A/L219A/V221A/L222A).
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ABCA1 p.Leu222Ala 21209084:158:34
status: NEW166 In contrast to apoA-I(L218A/L219A/V221A/L222A), prelipidation of either apoA-I(⌬1-59) or apoA-I(⌬1-59/⌬185-243) did not rescue their FIGURE 4.
X
ABCA1 p.Leu222Ala 21209084:166:40
status: NEW178 Binding and transport of rHDL containing WT apoA-I or apoA-I(L218A/L219A/V221A/L222A).
X
ABCA1 p.Leu222Ala 21209084:178:79
status: NEW181 D, specific binding at 4 °C of 10 g/ml 125 I-rHDL particles containing either WT apoA-I or apoA-I(L218A/L219A/V221A/L222A) was determined.
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ABCA1 p.Leu222Ala 21209084:181:129
status: NEW182 E, specific transport of 10 g/ml 125 I-rHDL particles containing either WT apoA-I or apoA-I(L218A/L219A/V221A/L222A) through a monolayer of ECs was determined.
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ABCA1 p.Leu222Ala 21209084:182:118
status: NEW187 down of ABCG1 and SR-BI but not of ABCA1 decreased the specific transendothelial transport of prelipidated WT apoA-I (Fig. 8A) and prelipidated apoA-I(L218A/L219A/V221A/ L222A) (Fig. 8B).
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ABCA1 p.Leu222Ala 21209084:187:170
status: NEW188 The reduction of the transport capacity of lipidated apoA-I(L218A/L219A/V221A/L222A) by knockdown of ABCG1 or SR-BI was smaller (-44% Ϯ7%) compared with lipidated WT apoA-I (-60% Ϯ 15%).
X
ABCA1 p.Leu222Ala 21209084:188:78
status: NEW194 Also, in our endothelial transwell cell culture model, both apoA-I(⌬185-243) and apoA-I(L218A/L219A/V221A/L222A) failed to form HDL-like particles although only the specific but not the nonspecific fraction of transendothelial transport was abolished.
X
ABCA1 p.Leu222Ala 21209084:194:113
status: NEW207 The formation of a high affinity complex of apoA-I with ABCA1 is thought to play FIGURE8.RoleofABCA1,ABCG1,andSR-BIinthetransportofrHDLcontainingWTapoA-IorapoA-I(L218A/L219A/V221A/L222A).ECsweretransfected with siRNA coding for ABCA1, ABCG1, SR-BI and not coding siRNA.
X
ABCA1 p.Leu222Ala 21209084:207:180
status: NEW211 B, specific transport of rHDL containing apoA-I(L218A/ L219A/V221A/L222A).
X
ABCA1 p.Leu222Ala 21209084:211:67
status: NEW218 The apoA-I(L218A/L219A/V221A/L222A) mutant, which shows strongly reduced specific but normal nonspecific transendothelial transport (data not shown), was not recovered as a lipidated particle (Fig. 3).
X
ABCA1 p.Leu222Ala 21209084:218:29
status: NEW221 These downstream pathways may be shared with the transport of HDL because knockdown of ABCG1 or SR-BI inhibited the specific transport of native HDL (15) as well as rHDL containing either WT apoA-I or apoA-I(L218A/L219A/ V221A/L222A) (Fig. 8).
X
ABCA1 p.Leu222Ala 21209084:221:227
status: NEW222 In agreement with normal binding of rHDL containing apoA-I(L218A/L219A/V221A/L222A), ldlA-7 cells expressing SR-BI were previously found to bind rHDL containing apoA-I(⌬185-243) with affinity similar to that of rHDL with WT apoA-I (46).
X
ABCA1 p.Leu222Ala 21209084:222:77
status: NEW45 Generation of Adenoviruses Expressing ApoA-I(L218A/L219A/ V221A/L222A)-The apoA-I gene lacking the BglII restriction site (that is present at nucleotide positions 181 of the genomic sequence relative to the ATG codon of the gene) was cloned into the pcDNA3.1 vector to generate the pcDNA3.1- apoA-I(èc;BglII) plasmid as described (30).
X
ABCA1 p.Leu222Ala 21209084:45:64
status: NEW55 The mutant protein was isolate from the culture medium of HTB-13 cells infected with the apoA-I(L218A/ L219A/V221A/L222A)-expressing adenovirus as described (22, 26).
X
ABCA1 p.Leu222Ala 21209084:55:115
status: NEW92 The two mutants with a defective carboxyl-terminal sequence, apoA-I(èc;185-243) and apoA-I(L218A/L219A/V221A/L222A), showed 50 and 80% decreases in total and specific endothelial binding, respectively (Fig. 1).
X
ABCA1 p.Leu222Ala 21209084:92:113
status: NEW101 The results are represented as means afe; S.D. (error bars) of at least three individual experiments. Transendothelial ApoA-I Transport Is a Two-step Process 7746 binant WT apoA-I, and apoA-I(èc;144-165) did not differ from each other whereas the apoA-I(èc;185-243) and apoA-I(L218A/ L219A/V221A/L222A) mutants showed strongly reduced total and specific cell association, and the apoA-I(èc;1-59) and apoA-I(èc;1-59/èc;185-243) mutants showed massively increased total cell association which could not be competed by WT apoA-I (data not shown).
X
ABCA1 p.Leu222Ala 21209084:101:308
status: NEW107 In contrast, the specific transports of apoA-I(èc;185-243) and apoA-I(L218A/L219A/V221A/L222A) were decreased by 90%.
X
ABCA1 p.Leu222Ala 21209084:107:92
status: NEW110 Therefore, we compared the particle sizes of WT apoA-I and the dysfunctional apoA-I(L218A/L219A/V221A/L222A) mutant before and after transport through ECs (Fig. 3).
X
ABCA1 p.Leu222Ala 21209084:110:102
status: NEW115 We therefore assume that this fraction represents lipid-free aggregates of apoA-I(L218A/ L219A/V221A/L222A).
X
ABCA1 p.Leu222Ala 21209084:115:101
status: NEW136 Binding and Transport of Reconstituted HDL Containing WT ApoA-I or ApoA-I(L218A/L219A/V221A/L222A)-Next, we exploited the apoA-I(L218A/L219A/V221A/L222A) mutant with defects in ABCA1-mediated lipid efflux as well as specific endothelial binding and transport to test the hypothesis that transendothelial transport of lipid-free apoA-I occurs by a two-step mechanism in which apoA-I is first lipidated by ABCA1-dependent lipid efflux to then undergo ABCA1-independent transport through ECs.
X
ABCA1 p.Leu222Ala 21209084:136:92
status: NEWX
ABCA1 p.Leu222Ala 21209084:136:147
status: NEW137 We first lipidated WT apoA-I or apoA-I(L218A/L219A/V221A/L222A).
X
ABCA1 p.Leu222Ala 21209084:137:57
status: NEW140 rHDL containing apoA-I(L218A/L219A/ V221A/L222A) were slightly less negatively charged than rHDL containing WT apoA-I (Fig. 6A).
X
ABCA1 p.Leu222Ala 21209084:140:42
status: NEW146 Thus prelipidation can overcome the binding and transport defects of the dysfunctional apoA-I(L218A/L219A/V221A/L222A) mutant.
X
ABCA1 p.Leu222Ala 21209084:146:112
status: NEW152 Particle size of WT apoA-I and apoA-I(L218A/L219A/V221A/L222A) before and after transport through ECs.
X
ABCA1 p.Leu222Ala 21209084:152:56
status: NEW156 B, 125 I-apoA-I(L218A/L219A/V221A/L222A).
X
ABCA1 p.Leu222Ala 21209084:156:34
status: NEW164 In contrast to apoA-I(L218A/L219A/V221A/L222A), prelipidation of either apoA-I(èc;1-59) or apoA-I(èc;1-59/èc;185-243) did not rescue their FIGURE 4.
X
ABCA1 p.Leu222Ala 21209084:164:40
status: NEW176 Binding and transport of rHDL containing WT apoA-I or apoA-I(L218A/L219A/V221A/L222A).
X
ABCA1 p.Leu222Ala 21209084:176:79
status: NEW179 D, specific binding at 4 &#b0;C of 10 òe;g/ml 125 I-rHDL particles containing either WT apoA-I or apoA-I(L218A/L219A/V221A/L222A) was determined.
X
ABCA1 p.Leu222Ala 21209084:179:127
status: NEW180 E, specific transport of 10 òe;g/ml 125 I-rHDL particles containing either WT apoA-I or apoA-I(L218A/L219A/V221A/L222A) through a monolayer of ECs was determined.
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ABCA1 p.Leu222Ala 21209084:180:117
status: NEW185 Transendothelial ApoA-I Transport Is a Two-step Process MARCH 11, 2011ߦVOLUME 286ߦNUMBER 10 JOURNAL OF BIOLOGICAL CHEMISTRY down of ABCG1 and SR-BI but not of ABCA1 decreased the specific transendothelial transport of prelipidated WT apoA-I (Fig. 8A) and prelipidated apoA-I(L218A/L219A/V221A/ L222A) (Fig. 8B).
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ABCA1 p.Leu222Ala 21209084:185:308
status: NEW186 The reduction of the transport capacity of lipidated apoA-I(L218A/L219A/V221A/L222A) by knockdown of ABCG1 or SR-BI was smaller (afa;44% afe;7%) compared with lipidated WT apoA-I (afa;60% afe; 15%).
X
ABCA1 p.Leu222Ala 21209084:186:78
status: NEW192 Also, in our endothelial transwell cell culture model, both apoA-I(èc;185-243) and apoA-I(L218A/L219A/V221A/L222A) failed to form HDL-like particles although only the specific but not the nonspecific fraction of transendothelial transport was abolished.
X
ABCA1 p.Leu222Ala 21209084:192:112
status: NEW205 The formation of a high affinity complex of apoA-I with ABCA1 is thought to play FIGURE8.RoleofABCA1,ABCG1,andSR-BIinthetransportofrHDLcontainingWTapoA-IorapoA-I(L218A/L219A/V221A/L222A).ECsweretransfected with siRNA coding for ABCA1, ABCG1, SR-BI and not coding siRNA.
X
ABCA1 p.Leu222Ala 21209084:205:180
status: NEW209 B, specific transport of rHDL containing apoA-I(L218A/ L219A/V221A/L222A).
X
ABCA1 p.Leu222Ala 21209084:209:67
status: NEW216 The apoA-I(L218A/L219A/V221A/L222A) mutant, which shows strongly reduced specific but normal nonspecific transendothelial transport (data not shown), was not recovered as a lipidated particle (Fig. 3).
X
ABCA1 p.Leu222Ala 21209084:216:29
status: NEW219 These downstream pathways may be shared with the transport of HDL because knockdown of ABCG1 or SR-BI inhibited the specific transport of native HDL (15) as well as rHDL containing either WT apoA-I or apoA-I(L218A/L219A/ V221A/L222A) (Fig. 8).
X
ABCA1 p.Leu222Ala 21209084:219:227
status: NEW220 In agreement with normal binding of rHDL containing apoA-I(L218A/L219A/V221A/L222A), ldlA-7 cells expressing SR-BI were previously found to bind rHDL containing apoA-I(èc;185-243) with affinity similar to that of rHDL with WT apoA-I (46).
X
ABCA1 p.Leu222Ala 21209084:220:77
status: NEW[hide] Role of the hydrophobic and charged residues in th... J Lipid Res. 2013 Dec;54(12):3281-92. doi: 10.1194/jlr.M038356. Epub 2013 Aug 29. Fotakis P, Kateifides AK, Gkolfinopoulou C, Georgiadou D, Beck M, Grundler K, Chroni A, Stratikos E, Kardassis D, Zannis VI
Role of the hydrophobic and charged residues in the 218-226 region of apoA-I in the biogenesis of HDL.
J Lipid Res. 2013 Dec;54(12):3281-92. doi: 10.1194/jlr.M038356. Epub 2013 Aug 29., [PMID:23990662]
Abstract [show]
We investigated the significance of hydrophobic and charged residues 218-226 on the structure and functions of apoA-I and their contribution to the biogenesis of HDL. Adenovirus-mediated gene transfer of apoA-I[L218A/L219A/V221A/L222A] in apoA-I(-)/(-) mice decreased plasma cholesterol and apoA-I levels to 15% of wild-type (WT) control mice and generated pre-beta- and alpha4-HDL particles. In apoA-I(-)/(-) x apoE(-)/(-) mice, the same mutant formed few discoidal and pre-beta-HDL particles that could not be converted to mature alpha-HDL particles by excess LCAT. Expression of the apoA-I[E223A/K226A] mutant in apoA-I(-)/(-) mice caused lesser but discrete alterations in the HDL phenotype. The apoA-I[218-222] and apoA-I[E223A/K226A] mutants had 20% and normal capacity, respectively, to promote ABCA1-mediated cholesterol efflux. Both mutants had approximately 65% of normal capacity to activate LCAT in vitro. Biophysical analyses suggested that both mutants affected in a distinct manner the structural integrity and plasticity of apoA-I that is necessary for normal functions. We conclude that the alteration of the hydrophobic 218-222 residues of apoA-I disrupts apoA-I/ABCA1 interactions and promotes the generation of defective pre-beta particles that fail to mature into alpha-HDL subpopulations, thus resulting in low plasma apoA-I and HDL. Alterations of the charged 223, 226 residues caused milder but discrete changes in HDL phenotype.
Comments [show]
None has been submitted yet.
No. Sentence Comment
7 Adenovirus-mediated gene transfer of apoA-I[L218A/ L219A/V221A/L222A] in apoA-I d1a;/d1a; mice decreased plasma cholesterol and apoA-I levels to 15% of wild-type (WT) control mice and generated pre-beta-and ॷ4-HDL particles.
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ABCA1 p.Leu222Ala 23990662:7:63
status: NEW21 Published, JLR Papers in Press, August 29, 2013 DOI 10.1194/jlr.M038356 Role of the hydrophobic and charged residues in the 218-226 region of apoA-I in the biogenesis of HDL 1 Panagiotis Fotakis,* ,ߤ Andreas K. Kateifides,* ,ߤ Christina Gkolfinopoulou, &#a7; Dimitra Georgiadou, &#a7; Melissa Beck,* ,ߤ Katharina Gr&#fc;ndler,* Angeliki Chroni, &#a7; Efstratios Stratikos, &#a7; Dimitris Kardassis, ߤ and Vassilis I. Zannis 2, * Whitaker Cardiovascular Institute,* Boston University School of Medicine, Boston, MA 02118; Department of Biochemistry,ߤ University of Crete Medical School, Heraklion, Crete, Greece 71110; and National Center for Scientific Research "Demokritos",&#a7; Athens, Greece 15310 Abbreviations: ANS, 8-anilino-1-naphthalene-sulfonate; apoA-I[218-222], the apoA-I carrying the L218A/L219A/V221A/L222A mutations; apoA-I[E223A/K226A], the apoA-I carrying the E223A/K226A mutations apoA-I afa;/afa; , apoA-I-deficient; apoA-I afa;/afa; &#d7; apoE afa;/afa; , apoA-I and apoE double-deficient; CD, circular dichroism; cpt-cAMP, 8-(4-chlorophenylthio) adenosine 3':5'-cyclic monophosphatase; DMPC, dimyristoyl-L-ॷ- phosphatidylcholine; EM, electron microscopy; FPLC, fast-protein liquid chromatography; GdnHCl, guanidine hydrochloride; HEK293, human embryonic kidney 293; HTB-13, SW 1783 human astrocytoma; pfu, plaque-forming unit; POPC, beta-oleoyl-ॹ-palmitoyl-L-ॷ-phosphatidylcholine; rHDL, reconstituted HDL; WMF, wavelength of maximum fluorescence; WT, wild-type.
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ABCA1 p.Leu222Ala 23990662:21:846
status: NEW60 In addition to the drastic effect of the L218A/L219A/ V221A/L222A mutations on the biogenesis of HDL, the mutants also inhibited the ability of lipid-free apoA-I to promote transendothelial transport (20), as well as its bactericidal activity against Gram-negative bacteria (21), indicating the importance of the 218-222 residues for the functions of apoA-I.
X
ABCA1 p.Leu222Ala 23990662:60:60
status: NEW74 The L218A/L219A/V221A/L222A mutations in apoA-I resulted in a great increase in plasma apoA-IV that floated in the IDL/LDL/HDL2/HDL3 region (Fig. 3D and supplementary Fig. II) and the presence of apoB-48 in the HDL region (Fig. 3E).
X
ABCA1 p.Leu222Ala 23990662:74:22
status: NEW132 Effect of the L218A/L219A/V221A/L222A and E223A/ K226A mutations on the ॷ-helical content, thermal unfolding, chemical unfolding, and hydrophobic surface exposure of apoA-I To test whether the functional changes of the two apoA-I mutants are accompanied by changes in the structure and conformation of the protein, we used an array of biophysical assays to evaluate the effects of these mutations (Fig. 6).
X
ABCA1 p.Leu222Ala 23990662:132:32
status: NEW142 L218A/L219A/V221A/L222A and E223A/K226A mutations alter the functional and physicochemical properties of apoA-I The in vitro experiments showed that, compared with WT apoA-I, the capacity of the apoA-I[218-222] mutant to promote ABCA1-mediated cholesterol efflux and to activate LCAT was 20% and 66%, respectively.
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ABCA1 p.Leu222Ala 23990662:142:18
status: NEW173 Calculated biophysical parameters for WT and mutant apoA-I forms Mutation Circular Dichroism Thermal Denaturation Chemical Denaturation ANS Binding ApoA-I ॷ-Helix Tm (&#b0;C) Slope Cooperativity Index (n) èc;H (kcal/mol) èc;GD o (kcal/mol) D1/2 (M) mc (kcal mol afa;2 ) Fold Increasea WT 60.0 &#b1; 1.5 55.6 &#b1; 0.4 8.3 &#b1; 0.4 6.4 &#b1; 0.2 25.9 &#b1; 1.5 6.3 &#b1; 0.4 1.01 &#b1; 0.02 6.3 &#b1; 0.4 6.0 &#b1; 0.4 L218A/L219A/V221A/L222A 52.7 &#b1; 1.6b 56.1 &#b1; 0.8 4.6 &#b1; 0.2 b 9.7 &#b1; 0.6 b 46.4 &#b1; 2.4 b 6.6 &#b1; 0.4 1.00 &#b1; 0.03 6.4 &#b1; 0.4 3.5 &#b1; 0.2 b E223A/K226A 55.8 &#b1; 1.1 c 53.4 &#b1; 0.2 b 10.4 &#b1; 1.4 d 5.3 &#b1; 0.7 b 21.01 &#b1; 2.2 e 2.5 &#b1; 0.2 b 0.88 &#b1; 0.02 f 2.8 &#b1; 0.1 b 9.6 &#b1; 0.5 b Values are means &#b1; SD from three or four experiments.
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ABCA1 p.Leu222Ala 23990662:173:454
status: NEW[hide] HDL biogenesis, remodeling, and catabolism. Handb Exp Pharmacol. 2015;224:53-111. doi: 10.1007/978-3-319-09665-0_2. Zannis VI, Fotakis P, Koukos G, Kardassis D, Ehnholm C, Jauhiainen M, Chroni A
HDL biogenesis, remodeling, and catabolism.
Handb Exp Pharmacol. 2015;224:53-111. doi: 10.1007/978-3-319-09665-0_2., [PMID:25522986]
Abstract [show]
In this chapter, we review how HDL is generated, remodeled, and catabolized in plasma. We describe key features of the proteins that participate in these processes, emphasizing how mutations in apolipoprotein A-I (apoA-I) and the other proteins affect HDL metabolism. The biogenesis of HDL initially requires functional interaction of apoA-I with the ATP-binding cassette transporter A1 (ABCA1) and subsequently interactions of the lipidated apoA-I forms with lecithin/cholesterol acyltransferase (LCAT). Mutations in these proteins either prevent or impair the formation and possibly the functionality of HDL. Remodeling and catabolism of HDL is the result of interactions of HDL with cell receptors and other membrane and plasma proteins including hepatic lipase (HL), endothelial lipase (EL), phospholipid transfer protein (PLTP), cholesteryl ester transfer protein (CETP), apolipoprotein M (apoM), scavenger receptor class B type I (SR-BI), ATP-binding cassette transporter G1 (ABCG1), the F1 subunit of ATPase (Ecto F1-ATPase), and the cubulin/megalin receptor. Similarly to apoA-I, apolipoprotein E and apolipoprotein A-IV were shown to form discrete HDL particles containing these apolipoproteins which may have important but still unexplored functions. Furthermore, several plasma proteins were found associated with HDL and may modulate its biological functions. The effect of these proteins on the functionality of HDL is the topic of ongoing research.
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No. Sentence Comment
76 Adenovirus-mediated gene transfer of these mutants in apoA-I / x apoE / mice (Fotakis et al. 2013a, b) showed that compared to the WT apoA-I, the expression of an apoA-I[L218A/L219A/V221A/L222A] mutant decreased plasma cholesterol, apoA-I, and HDL cholesterol levels and generated preb2;- and b1;4 HDL subpopulations (Fotakis et al. 2013a) (Table 1 and Fig. 3a-g).
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ABCA1 p.Leu222Ala 25522986:76:188
status: NEW77 To eliminate the involvement of apoE in the generation of apoE-containing HDL particles (Kypreos and Zannis 2007), the apoA-I[L218A/L219A/V221A/L222A] mutant was expressed in apoA-I / x apoE / mice via adenovirus-mediated gene transfer (Fotakis et al. 2013a).
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ABCA1 p.Leu222Ala 25522986:77:144
status: NEW81 Table 1 Plasma lipids and hepatic mRNA levels of apoA-I / or apoA-I / x apoE / mice expressing WT and mutant forms of apoA-I in the presence and absence of LCAT as indicated Protein expressed Total cholesterol (mg/dL) Triglycerides (mg/dL) Relative apoA-I mRNA (%) apoA-I plasma levels (mg/dL) WT apoA-I in apoA-I / mice 278 74 78 24 100 26 260 40 apoA-I[L218A/L219A/V221A/ L222A] in apoA-I / mice 45 14 50 20 95 24 41 5 WT apoA-I in apoA-I / x apoE / mice 1,343 104 294 129 100 13 - apoA-I[L218A/L219A/V221A/ L222A] in apoA-I / x apoE / mice 778 52 18 2 92 23 - apoA-I[L218A/L219A/V221A/ L222A] plus LCAT in apoA-I / x apoE / mice 754 122 37 10 90 3 - Fig. 3 (a-g) ApoA-I mutations and their effect on the HDL phenotypes.
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ABCA1 p.Leu222Ala 25522986:81:382
status: NEWX
ABCA1 p.Leu222Ala 25522986:81:532
status: NEWX
ABCA1 p.Leu222Ala 25522986:81:617
status: NEW82 Analysis of plasma of apoA-I / x apoE / mice infected with adenoviruses expressing the WT apoA-I or the apoA-I [L218A/L219A/V221A/L222A] mutant, as indicated, by density gradient ultracentrifugation and SDS-PAGE (a, e).
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ABCA1 p.Leu222Ala 25522986:82:130
status: NEW83 EM analysis of HDL fractions 6-7 obtained from apoA-I / x apoE / mice expressing the WT apoA-I or the apoA-I[L218A/L219A/V221A/L222A] mutant, as indicated, following density gradient ultracentrifugation of plasma (b, f).
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ABCA1 p.Leu222Ala 25522986:83:127
status: NEW85 Two-dimensional gel electrophoresis of plasma of apoA-I / x apoE / mice infected with adenoviruses expressing WT apoA-I or the apoA-I[L218A/L219A/V221A/L222A] mutant, as indicated (d, g) These particles may originate from apoB-48 containing lipoproteins that are found in the HDL fractions (Fig. 3c).
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ABCA1 p.Leu222Ala 25522986:85:152
status: NEW88 Co-expression of the apoA-I[L218A/L219A/V221A/L222A] mutant and human LCAT in apoA-I / x apoE / mice did not correct the plasma apoA-I levels and did not correct the aberrant HDL phenotype.
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ABCA1 p.Leu222Ala 25522986:88:46
status: NEW92 The phenotype produced by the apoA-I[L218A/L219A/V221A/L222A] mutations is distinct from all previously described phenotypes and cannot be corrected by overexpression of LCAT.
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ABCA1 p.Leu222Ala 25522986:92:55
status: NEW94 Although other interpretations are possible, the in vivo and in vitro data suggest that the interaction of the apoA-I [L218A/L219A/V221A/L222A] mutant with ABCA1 results in defective lipidation of apoA-I that leads to the generation of preb2;-HDL particles that are not a good substrate for LCAT.
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ABCA1 p.Leu222Ala 25522986:94:137
status: NEW99 The phenotype generated by the expression of the apoA-I[F225A/V227A/ F229A/L230A] mutant was similar to that obtained with the apoA-I[L218A/ L219A/V221A/L222A] mutant.
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ABCA1 p.Leu222Ala 25522986:99:153
status: NEW421 ApoA-I mutants with defective C-terminal apoA-I[Ɗ(185-243)] and apoA-I[L218A/L219A/V221A/ L222A] had 80 % decreased specific binding and 90 % decreased specific transport by aortic endothelial cells.
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ABCA1 p.Leu222Ala 25522986:421:95
status: NEW