Background information
Fyn is a membrane-associated, non-receptor protein tyrosine kinase approximately 59kDa, which belongs to the Src family of cytoplasmic tyrosine kinases. Fyn is very strongly similar to mouse Fyn, v-yes and c-src. Fyn is expressed predominately in tissues of neuronal and hematopoietic origin. Neuronal Fyn and hematopoietic Fyn differ at the junction of the SH2 and kinase domains due to tissue specific alternative splicing. Fyn has been shown to be involved in B cell and T cell activation as well as keratinocyte differentiation. In T cells, Fyn associates with the T-cell antigen receptor and Thy1.The unique N terminal domain of Fyn interacts with the CD3 and eta chains of the TcR. Fyn can bind to other proteins (p82 and p116) through its SH2 and SH3 domains, which may act as substrates or regulators of Fyn activity. Fyn is highly expressed in brain suggesting that it may have a role in the sensory nervous network and in myelination at early stages of CNS formation.
