Mutagenic Analysis of the Putative ABCC6 Substrate-Binding Cavity Using a New Homology Model.
Mutagenic Analysis of the Putative ABCC6 Substrate-Binding Cavity Using a New Homology Model.
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DOI：
10.3390/ijms22136910
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发表时间：
2021-06-27
影响因子：
5.6
通讯作者：
van de Wetering K
中科院分区：
文献类型：
--
作者：
Szeri F;Corradi V;Niaziorimi F;Donnelly S;Conseil G;Cole SPC;Tieleman DP;van de Wetering K
ABCC6失活突变是罕见的遗传性矿化疾病弹性假黄色瘤的基础。ABCC6是一种ATP结合盒（ABC）积分膜蛋白，可介导ATP从肝细胞释放到血液中。释放的ATP在细胞外转化为焦磷酸盐，焦磷酸盐是一种关键的矿化抑制剂。尽管ABCC6与细胞ATP释放紧密相关，但ABCC6介导的ATP释放的分子细节仍然难以捉摸。目前大多数可用的数据支持ABCC6是ATP依赖的ATP外排泵的假设，这是ABC转运体前所未有的功能。这一假设暗示在ABCC6的底物结合腔中存在atp结合位点。我们进行了广泛的诱变研究，使用基于最近发表的密切同源物牛Abcc1的结构的新的同源模型来表征ABCC6的底物结合腔。白三烯C4 （LTC4）是ABCC1的高亲和力底物。我们诱变了ABCC6大鼠同源物rAbcc6中的14个氨基酸残基，这些氨基酸残基与LTC4结合腔中发现的ABCC1残基相对应。我们的功能表征表明，rAbcc6中的大多数氨基酸与牛Abcc1中LTC4结合口袋中发现的氨基酸相对应，对ATP外排并不重要。我们得出结论，ABCC6/rAbcc6底物结合腔中假定的ATP结合位点与牛Abcc1 ltc4结合位点不同。
Inactivating mutations in ABCC6 underlie the rare hereditary mineralization disorder pseudoxanthoma elasticum. ABCC6 is an ATP-binding cassette (ABC) integral membrane protein that mediates the release of ATP from hepatocytes into the bloodstream. The released ATP is extracellularly converted into pyrophosphate, a key mineralization inhibitor. Although ABCC6 is firmly linked to cellular ATP release, the molecular details of ABCC6-mediated ATP release remain elusive. Most of the currently available data support the hypothesis that ABCC6 is an ATP-dependent ATP efflux pump, an un-precedented function for an ABC transporter. This hypothesis implies the presence of an ATP-binding site in the substrate-binding cavity of ABCC6. We performed an extensive mutagenesis study using a new homology model based on recently published structures of its close homolog, bovine Abcc1, to characterize the substrate-binding cavity of ABCC6. Leukotriene C4 (LTC4), is a high-affinity substrate of ABCC1. We mutagenized fourteen amino acid residues in the rat ortholog of ABCC6, rAbcc6, that corresponded to the residues in ABCC1 found in the LTC4 binding cavity. Our functional characterization revealed that most of the amino acids in rAbcc6 corresponding to those found in the LTC4 binding pocket in bovine Abcc1 are not critical for ATP efflux. We conclude that the putative ATP binding site in the substrate-binding cavity of ABCC6/rAbcc6 is distinct from the bovine Abcc1 LTC4-binding site.
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DOI：
10.1073/pnas.1319582110
发表时间：
2013-12-10
影响因子：
11.1
作者：
Jansen, Robert S.;Kucukosmanoglu, Asli;van de Wetering, Koen
通讯作者：
van de Wetering, Koen
影响因子：
4.8
作者：
Conseil, Gwenaelle;Arama-Chayoth, May;Cole, Susan P. C.
通讯作者：
Cole, Susan P. C.
影响因子：
4.8
作者：
Ito, K;Olsen, SL;Cole, SPC
通讯作者：
Cole, SPC
影响因子：
4.8
作者：
Dunn, Patrick J.;Salm, Elizabeth J.;Tomita, Susumu
通讯作者：
Tomita, Susumu
DOI：
10.1161/atvbaha.114.304017
发表时间：
2014-09
期刊：
Arteriosclerosis, thrombosis, and vascular biology
影响因子：
--
作者：
Jansen RS;Duijst S;Mahakena S;Sommer D;Szeri F;Váradi A;Plomp A;Bergen AA;Oude Elferink RP;Borst P;van de Wetering K
通讯作者：
van de Wetering K