Modulates signaling by tyrosine phosphorylated cell surface receptors such as KIT and the EGF receptor/EGFR. Enhances the inhibition of mast cell activation mediated by the Lilrb4a receptor (PubMed:10026201). The SH2 regions may interact with other cellular components to modulate its own phosphatase activity against interacting substrates. Together with MTUS1, induces UBE2V2 expression upon angiotensin II stimulation. Plays a key role in hematopoiesis. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Monomer. Interacts with MTUS1 (By similarity). Interacts with MILR1 (tyrosine-phosphorylated) (PubMed:20526344). Interacts with KIT (PubMed:9528781). Interacts with SIRPA/PTPNS1 (PubMed:9712903). Interacts with FCRL2 and FCRL4 (By similarity). Interacts with CD84 (By similarity). Interacts with CD300LF (PubMed:14662855). Interacts with CDK2 (By similarity). Interacts with KIR2DL1; the interaction is enhanced by ARRB2 (By similarity). Interacts (via SH2 1 domain) with ROS1; the interaction is direct and promotes ROS1 dephosphorylation (By similarity). Interacts with EGFR; inhibits EGFR-dependent activation of MAPK/ERK (By similarity). Interacts with LYN (By similarity). Interacts with the tyrosine phosphorylated form of PDPK1 (By similarity). Interacts with CEACAM1 (via cytoplasmic domain); this interaction depends on the monomer/dimer equilibrium and is phosphorylation-dependent (PubMed:19948503, PubMed:9867848). Interacts with MPIG6B (via ITIM motif) (PubMed:23112346). Interacts with KLRI1 and KLRI2 (By similarity). Interacts with moesin/MSN. Interacts with Lilrb4a (when tyrosine phosphorylated); the interaction enhances Lilrb4a-mediated inhibition of mast cell activation (PubMed:10026201, PubMed:9973385). Interacts with CLEC12B (via ITIM motif). In neurons, translocates into the nucleus after treatment with angiotensin II. Shuttles between the cytoplasm and nucleus via its association with PDPK1 (By similarity). Expressed predominantly in hematopoietic cells. The N-terminal SH2 domain functions as an auto-inhibitory domain, blocking the catalytic domain in the ligand-free close conformation. Phosphorylated on tyrosine residues. Phosphorylation at Tyr-564 enhances phosphatase activity (By similarity). Binding of KITLG/SCF to KIT increases tyrosine phosphorylation. Defects in Ptpn6 are the cause of the motheaten (me) or viable motheaten (mev) phenotypes. Mice homozygous for the recessive allelic mutations develop severe defects in hematopoiesis. Belongs to the protein-tyrosine phosphatase family. Non-receptor class 2 subfamily.