Differential Effects of Progressive Familial Intrahepatic Cholestasis Type 1 and Benign Recurrent Intrahepatic Cholestasis Type 1 Mutations on Canalicular Localization of ATP8B1
Differential Effects of Progressive Familial Intrahepatic Cholestasis Type 1 and Benign Recurrent Intrahepatic Cholestasis Type 1 Mutations on Canalicular Localization of ATP8B1
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DOI：
10.1002/hep.23158
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发表时间：
2009-11-01
期刊：
影响因子：
13.5
通讯作者：
Paulusma, Coen C.
中科院分区：
文献类型：
--
作者：
Folmer, Dineke E.;van der Mark, Vincent A.;Paulusma, Coen C.
ATP 8B 1突变导致进行性家族性肝内胆汁淤积1型（PFIC 1）和良性复发性肝内胆汁淤积I型（BRIC 1），形成胆汁淤积性疾病谱。PFIC 1是一种进行性的终末期肝病，而BRIC 1患者患有自发消退的胆汁淤积发作期。目前尚不清楚突变的类型和位置与PFIC 1和BRIC 1临床表现的关系。ATP 8B 1定位于肝细胞的小管膜;在那里它介导磷脂酰丝氨酸的向内易位。ATP 8B 1与CDC 50 A相互作用，这是内质网出口和质膜定位所需的。在这项研究中，我们分析了一组错义突变导致PFIC 1（G308 V，D554 N，G1040 R）或BRIC 1（D 70 N，166 11）。此外，我们纳入了两个与妊娠肝内胆汁淤积症（ICP）相关的突变（D 70 N，R867 C）。我们研究了这些突变对中国仓鼠卵巢细胞中蛋白质稳定性和与CDC 50 A相互作用的影响，并研究了WIF-B 9细胞中的亚细胞定位。研究的六种突变中有三种蛋白质稳定性降低。三分之二的PFIC 1突变蛋白不与CDC 50 A相互作用，而BRIC 1/ICP突变体显示减少的相互作用。重要的是，在WIF-B 9细胞的小管膜中没有检测到PFIC 1突变体，而所有BRIC 1/ICP突变体显示与野生型ATP 8B 1相同的细胞染色模式。我们的数据表明PFIC 1突变导致小管表达的完全缺失，而在BRIC 1/ICP中，残余蛋白在小管膜中表达。结论：这些数据为PFIC 1和BRIC 1表型之间的严重程度差异提供了解释。（《肝脏学》2009年;50：1597-1605）
Mutations in ATP8B1 cause progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis type I (BRIC1), forming a spectrum of cholestatic disease. Whereas PFIC1 is a progressive, endstage liver disease, BRIC1 patients suffer from episodic periods of cholestasis that resolve spontaneously. At present it is not dear how the type and location of the mutations relate to the clinical manifestations of PFIC1 and BRIC1. ATP8B1 localizes to the canalicular membrane of hepatocytes; where it mediates the inward translocation of phosphatidylserine. ATP8B1 interacts with CDC50A, which is required for endoplasmic reticulum exit and plasma membrane localization. In this study we analyzed a panel of missense mutations causing PFIC1 (G308V, D554N, G1040R) or BRIC1 (D70N, 166 11). In addition, we included two mutations that have been associated with intrahepatic cholestasis of pregnancy (ICP) (D70N, R867C). We examined the effect of these mutations on protein stability and interaction with CDC50A in Chinese hamster ovary cells, and studied the subcellular localization in WIF-B9 cells. Protein stability was reduced for three out of six mutations studied. Two out of three PFIC1 mutant proteins did not interact with CDC50A, whereas BRIC1/ICP mutants displayed reduced interaction. Importantly, none of the PFIC1 mutants were detectable in the canalicular membrane of WIF-B9 cells, whereas all BRIC1/ICP mutants displayed the same cellular staining pattern as wild-type ATP8B1. Our data indicate that PFIC1 mutations lead to the complete absence of canalicular expression, whereas in BRIC1/ICP residual protein is expressed in the canalicular membrane. Conclusion: These data provide an explanation for the difference in severity between the phenotypes of PFIC1 and BRIC1. (HEPATOLOGY 2009;50: 1597-1605.)