{"id":895,"date":"2026-03-06T21:04:55","date_gmt":"2026-03-06T21:04:55","guid":{"rendered":"http:\/\/changingfaceofamerica.com\/?p=895"},"modified":"2026-03-06T21:04:55","modified_gmt":"2026-03-06T21:04:55","slug":"a-the-hek-293-cells-were-transiently-transfected-with-wt-gfp-bsep-pfic-ii-mutants-and-gly","status":"publish","type":"post","link":"https:\/\/changingfaceofamerica.com\/?p=895","title":{"rendered":"\ufeff== (A) The HEK 293 cells were transiently transfected with wt GFP-Bsep, PFIC II mutants and Gly"},"content":{"rendered":"

\ufeff== (A) The HEK 293 cells were transiently transfected with wt GFP-Bsep, PFIC II mutants and Gly. the wild-type (wt) Bsep, and their ubiquitination is usually increased by the proteasome inhibitors. Overexpression of several E3 ubiquitin ligases, which are involved in ER-associated degradation (ERAD), lead to the decrease of both mutant and wt Bsep. Gene knockdown studies revealed that this ERAD E3s Rma1 and TEB4 contribute to the degradation of G238V, while HRD1 contributes to the degradation of a mutant lacking the lumenal glycosylation domain name (Gly). Furthermore we present evidence that G982R weakly associates with various components of the ER quality control system. These data together demonstrate that this PFIC II mutants and Gly are degraded by the ERAD pathway. Bile secretion is Ets1<\/a> usually mediated by several ATP binding cassette (ABC) transporters located in the canalicular membrane of hepatocytes (for reviews, see [1,2]). Among these ABC transporters, the bile salt export pump (BSEP\/Bsep, ABCB11\/ABCb11) represents the primary if not the sole transport system for the canalicular excretion of bile salts [3,4]. Bile secretory failure results in cholestasis. Progressive familial intrahepatic cholestasis Minaprine dihydrochloride<\/a> (PFIC) of infancy represents a group of inherited cholestatic diseases that are classified into three subtypes. One of these subtypes, PFIC II, is usually associated with mutations in theBSEPgene [4,5]. PFIC I and PFIC III are caused by mutations in the genes encoding FIC I (ATP8B1) and MDR3 (ABCB4), respectively [6,7]. A large number of premature termination, missense and frame shift mutations in theBSEPgene have been identified from PFIC II patients. These mutations impair the canalicular location or the transport function (or both) of Bsep [8-13]. When different variants of Bsep were examined in model cell lines, several missense mutations reduced the expression level of the Bsep protein [8-10,13]. Since the mRNA transcript levels of the mutant Bsep are not affected [9,10,13], these data raise the possibility that these mutations may cause the Bsep protein to become unstable and degraded. This assumption is usually consistent with an earlier immunohistochemistry study that BSEP was not detected in many PFIC II patients [5]. The mechanism by which these mutations cause Bsep to become unstable and degraded is not known. In the present study, we have examined the impact of a number of missense PFIC II mutations on processing and stability of rat Bsep. In several genetic diseases like cystic fibrosis, ubiquitin and the proteasome have been implicated in the degradation of aberrant ABC Minaprine dihydrochloride transporters [14]. The most common mutation in cystic fibrosis patients is usually cystic fibrosis transmembrane conductance regulator (CFTR) F508, which causes the mutant CFTR protein, instead of being expressed at the cell surface, to be completely degraded at the ER by the proteasome, a multisubunit ATP-dependent protease in the cytosol. Inhibition of proteasomes also stabilized Bsep G238V, E297G and D482G when examined in Madin-Darby canine kidney (MDCK) cells and human embryonic kidney (HEK) cells [8,10,13]. These findings suggest that the proteasome plays a major role in the degradation of Minaprine dihydrochloride these BSEP mutants in PFIC II patients. In this paper, we assessed the contribution of the proteasome and lysosome to the degradation of the Bsep PFIC II mutants. Ubiquitination involves three key enzymes, namely an ubiquitin-activating enzyme (E1), an ubiquitin-conjugating enzyme (E2) that transiently carries the activated ubiquitin molecule, and an ubiquitin ligase (E3) that recognizes specific substrates and transfers the activated ubiquitin from the E2 to the substrate. Among these Minaprine dihydrochloride three enzymes, E3s are believed to be responsible for the high efficiency and exquisite selectivity of ubiquitination reactions [15]. The ER is the major site where newly synthesized membrane proteins such as Bsep enter the secretory pathway and fold. Only proteins that are correctly folded and assembled are usually able to leave the ER. Most misfolded or unassembled proteins are retained in the ER and subsequently degraded in the cytosol by a process known as the ER-associated protein degradation (ERAD). During the ERAD process,.<\/p>\n","protected":false},"excerpt":{"rendered":"

\ufeff== (A) The HEK 293 cells were transiently transfected with wt GFP-Bsep, PFIC II mutants and Gly. the wild-type (wt) Bsep, and their ubiquitination is usually increased by the proteasome inhibitors. Overexpression of several E3 ubiquitin ligases, which are involved in ER-associated degradation (ERAD), lead to the decrease of both mutant and wt Bsep. Gene […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-895","post","type-post","status-publish","format-standard","hentry","category-other-oxygenases-oxidases"],"_links":{"self":[{"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=\/wp\/v2\/posts\/895","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=895"}],"version-history":[{"count":1,"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=\/wp\/v2\/posts\/895\/revisions"}],"predecessor-version":[{"id":896,"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=\/wp\/v2\/posts\/895\/revisions\/896"}],"wp:attachment":[{"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=895"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=895"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/changingfaceofamerica.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=895"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}