Dephosphorylates a range of proteins, and thereby regulates cellular signaling cascades (PubMed:18559503). Dephosphorylates cellular tyrosine kinases, such as ERBB2 and PTK2B/PYK2, and thereby regulates signaling via ERBB2 and PTK2B/PYK2 (PubMed:17329398, PubMed:27134172). Selectively dephosphorylates ERBB2 phosphorylated at 'Tyr-1112', 'Tyr-1196', and/or 'Tyr-1248' (PubMed:27134172). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Interacts with TGFB1I1 (By similarity). Interacts with PSTPIP1 (PubMed:9857189). Interacts with PTK2B/PYK2 (PubMed:17329398). Interacts with LPXN (By similarity). Interacts with SORBS2; this interaction greatly enhances WASF1 dephosphorylation and might mediate partial translocation to focal adhesion sites (PubMed:18559503). Partial translocation to focal adhesion sites may be mediated by interaction with SORBS2. Phosphorylated by STK24/MST3 and this results in inhibition of its activity. Belongs to the protein-tyrosine phosphatase family. Non-receptor class 4 subfamily. Extended N-terminus.