PPP1R15A
Protein phosphatase 1 regulatory subunit 15A (PPP1R15A; also known as growth arrest and DNA damage-inducible protein GADD34) is a member of the protein family whose expression is up-regulated by growth arrest and DNA damage. It recruits the serine/threonine-protein phosphatase PP1 to dephosphorylate the translation initiation factor eIF-2A/EIF2S1, thereby reversing the shut-off of protein synthesis initiated by stress-inducible kinases and facilitating recovery of cells from stress[1]. PPP1R15a down-regulates the TGF-β signaling pathway by promoting dephosphorylation of TGFB1 by PP1, and may promote apoptosis by inducing TP53 phosphorylation on Ser-15[2].
[1] H.P. Harding et al. Ppp1r15 gene knockout reveals an essential role for translation initiation factor 2 alpha (eIF2α) dephosphorylation in mammalian development. Proc Natl Acad Sci U S A. 2009, 106(6), 1832–1837.
[2] E. Kojima et al. The function of GADD34 is a recovery from a shutoff of protein synthesis induced by ER stress: elucidation by GADD34-deficient mice. FASEB J. 2003 Aug;17(11):1573-5.