The function of ENSG00000088179 (PTPN4, protein tyrosine phosphatase non-receptor type 4) is as follows. Phosphatase that plays a role in immunity, learning, synaptic plasticity or cell homeostasis (PubMed:25825441, PubMed:27246854). Regulates neuronal cell homeostasis by protecting neurons against apoptosis (PubMed:20086240). Negatively regulates TLR4-induced interferon beta production by dephosphorylating adapter TICAM2 and inhibiting subsequent TRAM-TRIF interaction (PubMed:25825441). Also dephosphorylates the immunoreceptor tyrosine-based activation motifs/ITAMs of the TCR zeta subunit and thereby negatively regulates TCR-mediated signaling pathway (By similarity). May act at junctions between the membrane and the cytoskeleton. {ECO:0000250, ECO:0000250|UniProtKB:Q9WU22, ECO:0000269|PubMed:20086240, ECO:0000269|PubMed:25825441, ECO:0000269|PubMed:27246854}.