Tyrosine-protein kinase Lck (LCK)

Non-receptor tyrosine-protein kinase that plays an essential role in the selection and maturation of developing T- cells in the thymus and in the role of mature T-cells. Plays a key role in T-cell antigen receptor (TCR)-linked signal transduction pathways.

Constitutively linked to the cytoplasmic portions of the CD4 and CD8 surface receptors. Association of the TCR with a peptide antigen-bound MHC complex facilitates the interaction of CD4 and CD8 with MHC class II and class I molecules, respectively, thereby recruiting the related LCK protein to the area of the TCR/CD3 complex.