CHOP mediates endoplasmic reticulum stress-induced apoptosis in Gimap5-deficient T cells.

Autor: Steven C Pino, Bryan O'Sullivan-Murphy, Erich A Lidstone, Chaoxing Yang, Kathryn L Lipson, Agata Jurczyk, Philip diIorio, Michael A Brehm, John P Mordes, Dale L Greiner, Aldo A Rossini, Rita Bortell
Jazyk: angličtina
Rok vydání: 2009
Předmět:
Zdroj: PLoS ONE, Vol 4, Iss 5, p e5468 (2009)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0005468
Popis: Gimap5 (GTPase of the immunity-associated protein 5) has been linked to the regulation of T cell survival, and polymorphisms in the human GIMAP5 gene associate with autoimmune disorders. The BioBreeding diabetes-prone (BBDP) rat has a mutation in the Gimap5 gene that leads to spontaneous apoptosis of peripheral T cells by an unknown mechanism. Because Gimap5 localizes to the endoplasmic reticulum (ER), we hypothesized that absence of functional Gimap5 protein initiates T cell death through disruptions in ER homeostasis. We observed increases in ER stress-associated chaperones in T cells but not thymocytes or B cells from Gimap5(-/-) BBDP rats. We then discovered that ER stress-induced apoptotic signaling through C/EBP-homologous protein (CHOP) occurs in Gimap5(-/-) T cells. Knockdown of CHOP by siRNA protected Gimap5(-/-) T cells from ER stress-induced apoptosis, thereby identifying a role for this cellular pathway in the T cell lymphopenia of the BBDP rat. These findings indicate a direct relationship between Gimap5 and the maintenance of ER homeostasis in the survival of T cells.
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