Could play a significant role in the signal transduction of hematopoietic cells. May regulate tyrosine kinase activity of SRC- family members in brain by specifically phosphorylating their C- terminal regulatory tyrosine residue which acts as a negative regulatory site. It may play an inhibitory role in the control of T- cell proliferation. . This is the function of MATK (megakaryocyte-associated tyrosine kinase, Ensembl gene identifier ENSG00000007264).