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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Subcompartments of the plasma membrane are believed to be critical for lymphocyte responses, but few genetic tools are available to test their function. Here we describe a previously unknown X-linked B cell-deficiency syndrome in mice caused by mutations in Atp11c, which encodes a member of the P4 ATPase family thought to serve as 'flippases' that concentrate aminophospholipids in the cytoplasmic leaflet of cell membranes. Defective ATP11C resulted in a lower rate of phosphatidylserine translocation in pro-B cells and much lower pre-B cell and B cell numbers despite expression of pre-rearranged immunoglobulin transgenes or enforced expression of the prosurvival protein Bcl-2 to prevent apoptosis and abolished pre-B cell population expansion in response to a transgene encoding interleukin 7. The only other abnormalities we noted were anemia, hyperbilirubinemia and hepatocellular carcinoma. Our results identify an intimate connection between phospholipid transport and B lymphocyte function.
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PMID:ATP11C is critical for the internalization of phosphatidylserine and differentiation of B lymphocytes. 2182 67

Thrombocytopenia is one of the most frequently observed secondary complications in many pathological conditions including liver diseases, where hyperbilirubinemia is very common. The present study sought to find the cause of thrombocytopenia in unconjugated hyperbilirubinemic conditions. Unconjugated bilirubin (UCB), an end-product of heme catabolism, is known to have pro-oxidative and cytotoxic effects at high serum concentration. We investigated the molecular mechanism underlying the pro-apoptotic effect of UCB on human platelets in vitro, and followed it up with studies in phenylhydrazine-induced hyperbilirubinemic rat model and hyperbilirubinemic human subjects. UCB is indeed found to significantly induce platelet apoptotic events including elevated endogenous reactive oxygen species generation, mitochondrial membrane depolarization, increased intracellular calcium levels, cardiolipin peroxidation and phosphatidylserine externalization (p < 0.001) as evident by FACS analysis. The immunoblots show the elevated levels of cytosolic cytochrome c and caspase activation in UCB-treated platelets. Further, UCB is found to induce mitochondrial ROS generation leading to p38 activation, followed by downstream activation of p53, ultimately resulting in altered expression of Bcl-2 and Bax proteins as evident from immunoblotting. All these parameters conclude that elevated unconjugated bilirubin causes thrombocytopenia by stimulating platelet apoptosis via mitochondrial ROS-induced p38 and p53 activation.
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PMID:Unconjugated Bilirubin exerts Pro-Apoptotic Effect on Platelets via p38-MAPK activation. 2645 59