LCK
LCK is a non-receptor Src family tyrosine kinase, also known as tyrosine-protein kinase Lck and formerly named lymphocyte-specific protein tyrosine kinase. It is a key signalling molecule in T-cell antigen receptor pathways and in the selection and maturation of developing T-cells. Browse Assay Genie's current range of LCK research reagents below, or read on for the biology behind the target.
LCK is a non-receptor tyrosine-protein kinase with an essential role in the selection and maturation of developing T-cells in the thymus and in the function of mature T-cells. It is constitutively associated with the cytoplasmic portions of the CD4 and CD8 surface receptors. When the T-cell antigen receptor (TCR) engages a peptide-bound MHC complex, CD4 and CD8 interact with MHC class II and class I molecules respectively, which recruits LCK to the vicinity of the TCR-CD3 complex. LCK then phosphorylates tyrosine residues within the immunoreceptor tyrosine-based activation motifs (ITAMs) of the TCR-gamma chains and CD3 subunits, initiating TCR-CD3 signalling. The stimulated TCR then recruits the tyrosine kinase ZAP70, which LCK phosphorylates and activates, and a large number of signalling molecules follow, ultimately leading to lymphokine production.
LCK also contributes to signalling by other receptors. It associates directly with the cytoplasmic tail of CD2, which leads to its hyperphosphorylation and activation, and it takes part in the IL2 receptor pathway that controls the T-cell proliferative response, where IL2 binding increases LCK activity. It is expressed at all stages of thymocyte development and is required for maturation events governed by both the pre-TCR and the mature alpha beta TCR. Other reported substrates include RUNX3, PTK2B/PYK2, the microtubule-associated protein MAPT, RHOH and TYROBP.
The LCK gene belongs to the Src family of protein tyrosine kinases and to the protein kinase superfamily. The encoded protein has N-terminal sites for myristylation and palmitylation, a kinase domain, and SH2 and SH3 domains that mediate interactions with phosphotyrosine-containing and proline-rich motifs. It localises to the plasma membrane and pericentrosomal vesicles, and multiple alternatively spliced variants encoding different isoforms have been described.
LCK phosphorylates ITAMs in the TCR-CD3 complex and activates ZAP70, making it a central component for studying how antigen recognition is converted into signalling.
LCK is expressed at all stages of thymocyte development and is required for maturation events governed by the pre-TCR and the mature alpha beta TCR.
LCK is constitutively associated with CD4 and CD8 and is recruited to the TCR-CD3 complex when these co-receptors engage MHC molecules.
LCK activity increases on IL2 binding to its receptor and contributes to the pathway controlling the T-cell proliferative response.
LCK is a non-receptor tyrosine kinase that phosphorylates ITAM tyrosines on the TCR and CD3 subunits to start TCR-CD3 signalling. It then phosphorylates and activates ZAP70. It is essential for T-cell selection and maturation in the thymus and for mature T-cell function.
The HGNC name is LCK proto-oncogene, Src family tyrosine kinase, and UniProt calls the protein tyrosine-protein kinase Lck. The previous gene name was lymphocyte-specific protein tyrosine kinase. Multiple alternatively spliced variants encoding different isoforms have been described.
Yes. Mouse and rat both have an orthologous gene named Lck. In humans, LCK is a member of the Src family of tyrosine kinases and is classed in the SH2 domain and SH3 domain containing gene groups. Check the datasheet of any product for its validated reactivity.
Other T-cell signalling kinases, co-receptors and LCK substrates and pathway partners with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P06239; product specifications from Assay Genie datasheets.