Recruits the serine/threonine-protein phosphatase PPP1CA to prevents excessive phosphorylation of 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 (PubMed:26742780, PubMed:26095357). Down-regulates the TGF-beta signaling pathway by promoting dephosphorylation of TGFB1 by PP1 (PubMed:14718519). May promote apoptosis by inducing p53/TP53 phosphorylation on 'Ser-15' (PubMed:14635196). Plays an essential role in autophagy by tuning translation during starvation, thus enabling lysosomal biogenesis and a sustained autophagic flux (PubMed:32978159). Acts also a viral restriction factor by attenuating HIV-1 replication (PubMed:31778897). Mechanistically, mediates the inhibition of HIV-1 TAR RNA-mediated translation (PubMed:31778897). (Microbial infection) Promotes enterovirus 71 replication by mediating the internal ribosome entry site (IRES) activity of viral 5'-UTR. Interacts with PPP1CA (PubMed:15705855, PubMed:26095357). Interacts with EIF2S1 (PubMed:26095357). Interacts with PCNA (By similarity). Interacts with LYN and KMT2A/MLL1 (PubMed:11517336). Interacts with PPP1R1A and SMARCB1 (PubMed:12016208). Interacts with SMAD7 (PubMed:14718519). Interacts with BAG1 (PubMed:12724406). Interacts with NOX4 (PubMed:26742780). (Microbial infection) Interacts with enterovirus 71/EV71 non-structural protein precursor 3CD; this interaction promotes EV71 replication. Associates with membranes via an N-terminal amphipathic intramembrane region. Specifically produced in response to stress: in absence of stress, some upstream open reading frame (uORF) of this transcript is translated, thereby preventing its translation (PubMed:19131336). By methyl methanesulfonate and ionizing irradiation (PubMed:9153226). By IL24/interleukin-24 in melanoma cells; which induces apoptosis (PubMed:10490642, PubMed:12114539). By viral infection including enterovirus 71/EV71 or HIV-1 (PubMed:34985336,PubMed:31778897). Phosphorylated at multiple Ser/Thr residues. Phosphorylated on tyrosine by LYN; which impairs its antiproliferative activity. Phosphorylation at Tyr-262 enhances proteasomal degradation, this position is dephosphorylated by PTPN2. Polyubiquitinated. Exhibits a rapid proteasomal degradation with a half-life under 1 hour, ubiquitination depends on endoplasmic reticulum association. The phosphatase activity of the PPP1R15A-PP1 complex toward EIF2S1 is specifically inhibited by Salubrinal, a drug that protects cells from endoplasmic reticulum stress. Belongs to the PPP1R15 family.