ABCB4 p.Ser346Ile
| Predicted by SNAP2: | A: N (53%), C: N (57%), D: D (75%), E: D (71%), F: D (80%), G: D (59%), H: D (80%), I: D (71%), K: D (75%), L: D (85%), M: D (75%), N: N (66%), P: D (91%), Q: D (59%), R: D (75%), T: N (57%), V: D (71%), W: D (91%), Y: D (80%), |
| Predicted by PROVEAN: | A: N, C: N, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: N, P: D, Q: D, R: D, T: N, V: D, W: D, Y: D, |
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[hide] Expression and localization of hepatobiliary trans... Hepatology. 2005 May;41(5):1160-72. Keitel V, Burdelski M, Warskulat U, Kuhlkamp T, Keppler D, Haussinger D, Kubitz R
Expression and localization of hepatobiliary transport proteins in progressive familial intrahepatic cholestasis.
Hepatology. 2005 May;41(5):1160-72., [PMID:15841457]
Abstract [show]
Mutations of the bile salt export pump (BSEP) or the multidrug resistance P-glycoprotein 3 (MDR3) are linked to impaired bile salt homeostasis and lead to progressive familial intrahepatic cholestasis (PFIC)-2 and -3, respectively. The regulation of bile salt transporters in PFIC is not known. Expression of hepatobiliary transporters in livers of ten patients with a PFIC phenotype was studied by quantitative reverse transcription polymerase chain reaction, Western blotting, and immunofluorescence microscopy. PFIC was diagnosed by clinical and laboratory findings. All patients could be assigned to PFIC-2 or PFIC-3 by the use of BSEP- and MDR3-specific antibodies and by MDR3 gene-sequencing. Whereas in all PFIC-2 patients, BSEP immunoreactivity was absent from the canalicular membrane, in three PFIC-3 livers, canalicular MDR3 immunoreactivity was detectable. Serum bile salts were elevated to 276 +/- 233 and to 221 +/- 109 micromol/L in PFIC-2 and PFIC-3, respectively. Organic anion transporting polypeptide OATP1B1, OATP1B3, and MRP2 mRNA and protein levels were reduced, whereas sodium taurocholate cotransporting polypeptide (NTCP) was only reduced at the protein level, suggesting a posttranscriptional NTCP regulation. Whereas MRP3 mRNA and protein were not significantly altered, MRP4 messenger RNA and protein were significantly increased in PFIC. In conclusion, PFIC-2 may be reliably diagnosed by immunofluorescence, whereas the diagnosis of PFIC-3 requires gene-sequencing. Several mechanisms may contribute to elevated plasma bile salts in PFIC: reduced bile salt uptake via NTCP, OATP1B1, and OATP1B3, decreased BSEP-dependent secretion into bile, and increased transport back into plasma by MRP4. Upregulation of MRP4, but not of MRP3, might represent an important escape mechanism for bile salt extrusion in PFIC.
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No. Sentence Comment
109 Two different mutations were found in the three patients with detectable canalicular MDR3 immunoreactivity (S346I and A953D).
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ABCB4 p.Ser346Ile 15841457:109:108
status: NEW167 The mutation S346I was detected in 2 children (C6 and C7).
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ABCB4 p.Ser346Ile 15841457:167:13
status: NEW169 Similar to S346I, a canalicular staining pattern of MDR3 was observed in this patient.
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ABCB4 p.Ser346Ile 15841457:169:11
status: NEW[hide] Function and pathophysiological importance of ABCB... Pflugers Arch. 2007 Feb;453(5):601-10. Epub 2006 Apr 19. Oude Elferink RP, Paulusma CC
Function and pathophysiological importance of ABCB4 (MDR3 P-glycoprotein).
Pflugers Arch. 2007 Feb;453(5):601-10. Epub 2006 Apr 19., [PMID:16622704]
Abstract [show]
Like several other ATP-binding cassette (ABC) transporters, ABCB4 is a lipid translocator. It translocates phosphatidylcholine (PC) from the inner to the outer leaflet of the canalicular membrane of the hepatocyte. Its function is quite crucial as evidenced by a severe liver disease, progressive familial intrahepatic cholestasis type 3, which develops in persons with ABCB4 deficiency. Translocation of PC makes the phospholipid available for extraction into the canalicular lumen by bile salts. The primary function of biliary phospholipid excretion is to protect the membranes of cells facing the biliary tree against these bile salts: the uptake of PC in bile salt micelles reduces the detergent activity of these micelles. In this review, we will discuss the functional aspects of ABCB4 and the regulation of its expression. Furthermore, we will describe the clinical and biochemical consequences of complete and partial deficiency of ABCB4 function.
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No. Sentence Comment
141 Canalicular lipid transport defects can cause gallstone formation Cholesterol supersaturation of bile, which occurs in a large proportion of humans, leads to the formation of cholesterol Walker B; L556R 571del Truncation PFIC3 LPAC ICP 27 splice Truncation 132 del Truncation TM 2; W138R TM 12; 981 del Truncation Linker; Q636X Truncation TM 11; R957X Truncation TM 6; S346I E395G Walker B; I541F TM 12; G983S Walker A; V425M Walker A; T424A Walker B; D564G TM 7; F711S 180 del truncation 336 delT truncation Exon 22-23 del truncation F165I T175A TM 5; M301T TM 5; S320F 336 insT truncation Walker A; 432 insA truncation E528D L591Q W658stop 757 insT R788E A934T P1161S TM 5; S320F TM 8; G762ER144X Walker B; A546D Walker B; G535AALL 96 del Truncation Walker B; L556R 571del Truncation PFIC3 LPAC ICP 27 splice Truncation 132 del Truncation TM 2; W138R TM 12; 981 del Truncation Linker; Q636X Truncation TM 11; R957X Truncation TM 6; S346I E395G Walker B; I541F TM 12; G983S Walker A; V425M Walker A; T424A Walker B; D564G TM 7; F711S 180 del truncation 336 delT truncation Exon 22-23 del truncation F165I T175A TM 5; M301T TM 5; S320F 336 insT truncation Walker A; 432 insA truncation E528D L591Q W658stop 757 insT R788E A934T P1161S TM 5; S320F TM 8; G762ER144X Walker B; A546D Walker B; G535AALL 96 del Truncation Fig. 3 Summary of the known mutations and their localization in the protein, as identified in patients with PFIC type 3, LPAC syndrome (intrahepatic gallstone formation), and intrahepatic cholestasis of pregnancy (ICP).
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ABCB4 p.Ser346Ile 16622704:141:369
status: NEWX
ABCB4 p.Ser346Ile 16622704:141:934
status: NEW[hide] The wide spectrum of multidrug resistance 3 defici... Gastroenterology. 2001 May;120(6):1448-58. Jacquemin E, De Vree JM, Cresteil D, Sokal EM, Sturm E, Dumont M, Scheffer GL, Paul M, Burdelski M, Bosma PJ, Bernard O, Hadchouel M, Elferink RP
The wide spectrum of multidrug resistance 3 deficiency: from neonatal cholestasis to cirrhosis of adulthood.
Gastroenterology. 2001 May;120(6):1448-58., [PMID:11313315]
Abstract [show]
BACKGROUND & AIMS: We have specified the features of progressive familial intrahepatic cholestasis type 3 and investigated in 31 patients whether a defect of the multidrug resistance 3 gene (MDR3) underlies this phenotype. METHODS: MDR3 sequencing, liver MDR3 immunohistochemistry, and biliary phospholipid dosage were performed. RESULTS: Liver histology showed a pattern of biliary cirrhosis with patency of the biliary tree. Age at presentation ranged from the neonatal period to early adulthood. Sequence analysis revealed 16 different mutations in 17 patients. Mutations were identified on both alleles in 12 patients and only on 1 allele in 5. Four mutations lead to a frame shift, 2 are nonsense, and 10 are missense. An additional missense mutation probably representing a polymorphism was found in 5 patients. MDR3 mutations were associated with abnormal MDR3 canalicular staining and a low proportion of biliary phospholipids. Gallstones or episodes of cholestasis of pregnancy were found in patients or parents. Children with missense mutations had a less severe disease and more often a beneficial effect of ursodeoxycholic acid therapy. CONCLUSIONS: At least one third of the patients with a progressive familial intrahepatic cholestasis type 3 phenotype have a proven defect of MDR3. This gene defect should also be considered in adult liver diseases.
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No. Sentence Comment
126 MDR3 Mutations, Immunohistochemistry, and Biliary Phospholipids in Patients With High GGT PFIC (PFIC3) Patients Exon Nucleotide mutation Amino acid change Protein consequence Family MDR3 liver Phospholipids (%) bile Homozygous Deletion/Insertion M Y M I (sister of M Y) 2 111 A Ͼ G, splice donor site, exon/intron boundary 2/3 27 Frame shift in NH2 terminus, then truncation ND Absent ND 1.6 B Ka 6 426-432 del 132 Frame shift in TMD 2, 29 novel amino acids then truncation Mother ϩ/- Father ϩ/- 1 sibling ϩ/ϩ Absent ND B Sa 14 1744 del T 571 Frame shift, 15 novel amino acids then truncation Mother ϩ/- (ICP) Father ϩ/- 3 siblings ϩ/ϩ Absent ND P G 24 2975-2984 del Compound heterozygous 981 Frame shift in TMD 12, 3 novel amino acids then truncation Mother ϩ/ϩ Father ϩ/- ND 14.9 Bo S Bo N (sister of Bo S) 16 Nonsense 1938 C Ͼ T Q636X Linker region Truncation Mother ϩ/- Father ϩ/- 2 siblings ϩ/- Absent 2 ND B Aa 23 2901 C Ͼ T R957X TMD 11 Truncation Mother ϩ/- (ICP) Father ϩ/- 4 siblings ϩ/- or ϩ/ϩ Absent ND S F 10 Missense 1069 G Ͼ T S346I Serine to isoleucine in TMD6 Mother ϩ/- Father ϩ/- Faint 1 B H 11 1216 A Ͼ G E395G Glutamate to glycine between TMD 6 and first Walker A motif ND ND ND N I 14 1653 A Ͼ T I541F Isoleucine to phenylalanine in first Walker B motif Mother ϩ/- Father ϩ/- Absent ND M M 14 1699 T Ͼ G L556R Leucine to arginine in first Walker B motif ND ND ND P G 24 2979 G Ͼ A Compound heterozygous G983S Glycine to serine in TMD 12 Mother ϩ/- Father ϩ/ϩ ND 14.9 P A 6 Heterozygous Missense 444 T Ͼ C W138R Trytophan to arginine in TMD 2 Mother ϩ/- Father ϩ/ϩ ND 6.7 M Aa 12 1302 A Ͼ G T424A Threonine to alanine in first Walker A motif ND gallbladder lithiasis in father Faint 6.3 P K 12 1307 G Ͼ A V425M Valine to methionine in first Walker A motif ND Normal ND G A 14 1723 A Ͼ G D564G Aspartate to glycine in first Walker B motif ND ND ND G M 17 2132 T Ͼ C F711S Phenylalanine to serine in TMD 7 ND ND ND L M 16 Polymorphism 1986 A Ͼ G Homozygous R652G Arginine to glycine in linker region Mother ϩ/- (suspicion of ICP) Father ϩ/- ND ND Ga M " Heterozygous " " Mother ϩ/- Father ϩ/ϩ 1 sibling ϩ/- ND 9.7 L H L F (sister of L H) " Heterozygous " " ND ND ND VH C " Heterozygous " " Mother ϩ/ϩ Father ϩ/- ND ND NOTE.
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ABCB4 p.Ser346Ile 11313315:126:1180
status: NEW