C-Src Tyrosine Kinase, also known as CSK, regulates cell growth, migration, differentiation, and immune response. CSK Phosphorylates tyrosine residues located in the C-terminal tails of Src-family kinases. CSK is a protein coding gene which suppresses signaling by several surface receptors. Among CSK's related pathways are PI-3K cascade and Signaling by FGFR.