Interferes with CBL-mediated down-regulation and degradation of receptor-type tyrosine kinases. Promotes accumulation of activated target receptors, such as T-cell receptors, EGFR and PDGFRB, on the cell surface. Exhibits negligigle protein tyrosine phosphatase activity at neutral pH. May act as a dominant-negative regulator of UBASH3B-dependent dephosphorylation. May inhibit dynamin-dependent endocytic pathways by functionally sequestering dynamin via its SH3 domain. Homodimer or homooligomer. Interacts with CBL. Part of a complex containing CBL and activated EGFR. Interacts with ubiquitin and with mono-ubiquitinated proteins. Interacts with dynamin. Highest expression of UBASH3A in tissues belonging to the immune system, including spleen, peripheral blood leukocytes, thymus and bone marrow.