ABCMdb

PMID: 23483032

Aranyi T, Bacquet C, de Boussac H, Ratajewski M, Pomozi V, Fulop K, Brampton CN, Pulaski L, Le Saux O, Varadi A
Transcriptional regulation of the ABCC6 gene and the background of impaired function of missense disease-causing mutations.
Front Genet. 2013 Mar 11;4:27. doi: 10.3389/fgene.2013.00027. eCollection 2013., [PubMed]

Sentences

No. Mutations Sentence Comment

56 ABCC6 p.Arg1138Gln ABCC6 p.Arg1314Trp ABCC6 p.Gly1321Ser ABCC6 p.Val1298Phe ABCC6 p.Arg1339Cys Five missense mutations, V1298F and G1321S in the C-proximal ABC domain and R1138Q, R1314W, and R1339C at the transmission interface were included into the study. Login to comment 63 ABCC6 p.Gly1321Ser ABCC6 p.Val1298Phe Two of the variants (V1298F and G1321S) were found to be inactive, though they were capable of binding MgATP, their capacity to form a catalytic intermediate ("occluded nucleotide state") was impaired. Login to comment 64 ABCC6 p.Arg1138Gln ABCC6 p.Arg1314Trp R1138Q and R1314W were fully active in the transport assay. Login to comment 66 ABCC6 p.Arg1314Trp ABCC6 p.Gly1321Ser ABCC6 p.Val1298Phe The same was true for mutants G1321S, R1338Q, and R1314W, while the inactive V1298F was found mostly in the plasma membrane. Login to comment 71 ABCC6 p.Val1298Phe Only the inactive V1298F mutant showed plasma membrane localization at a similar high level as the wt. Login to comment 72 ABCC6 p.Gly1321Ser ABCC6 p.Arg1339Cys The R1339C and the G1321S proteins were found intracellularly (similar to the results obtained in the in vitro cell culture system). Login to comment 73 ABCC6 p.Arg1138Gln ABCC6 p.Arg1314Trp R1138Q and R1314W showed mostly intracellular appearance, Table 1 | Function and intracellular localization of ABCC6 variants. Login to comment 74 ABCC6 p.Arg1138Gln ABCC6 p.Arg1314Trp ABCC6 p.Gly1321Ser ABCC6 p.Val1298Phe ABCC6 p.Arg1339Cys ABCC6 variant Stability in Sf9 MgATP-binding ATPase catalytic intermediate Transport activity (% of WT) Plasma membrane localization in MDCKII cells Plasma membrane localization in mouse liver Intracellular localization in mouse liver WT Stable Yes Yes 100 +++++ +++++ - DABCC6 Stable n.d. n.d. <10 - - +++++ R1138Q Stable Yes Yes ~85 ++++ ++ +++ V1298F Stable Yes No <10 +++++ +++++ - G1321S Stable Yes No <10 - - +++++ R1314W Stable Yes Yes ~90 - + ++++ (ER) R1339C Unstable n.a. n.a. n.a. - - +++++ n.d., not determined; n.a., not applicable; ER, mostly retained with the endoplasmic reticulum. Login to comment 80 ABCC6 p.Gly1321Ser ABCC6 p.Val1298Phe Most probably the dramatically reduced transport activity of mutants V1298F and G1321S is the molecular background of the disease in patients with these variants (irrespective that in the case of the former one the correct plasma membrane targeting is preserved). Login to comment 87 ABCC6 p.Arg1138Gln ABCC6 p.Arg1314Trp ABCC6 p.Arg1339Cys R1138Q and R1314W were tested, along with R1339C and the WT protein as non-functional and functional controls respectively. Login to comment 89 ABCC6 p.Arg1339Cys We have found that R1314 shows ER retain, as it colocalized with an ER-marker in mouse hepatocytes, while R1338Q and R1339C was not found in this location. Login to comment 90 ABCC6 p.Arg1339Cys Oral treatment of the animals with 4-PBA before HTVI resulted in no effect on the intracellular localization of R1338Q and R1339C. Login to comment 91 ABCC6 p.Arg1314Trp However, treatment of mice with 4-PBA improved the cellular localization of R1314W (Figure 1D, left panels), which was confirmed in MDCKII cells (Figure 1D, right panels). Login to comment