High impact information on C6orf21

• A global proteomics approach identifies novel phosphorylated signaling proteins in GPVI-activated platelets: Involvement of G6f, a novel platelet Grb2-binding membrane adapter [1].
• G6f tyrosine phoshporylation was also found to take place in response to collagen, although not in response to the G protein-coupled receptor agonists, thrombin and ADP [1].
• With this approach including hydrazide bead affinity trapping, the immunoglobulin receptor G6f, which is known to couple to the Ras-mitogen-activated protein kinase pathway in the immune system, was shown here for the first time to be present in human platelets [2].
• These results suggest a coupling of G6f with downstream signal transduction pathways involving Grb2 and Grb7, including the Ras-MAP kinase pathway [3].
• The intracellular tail of G6f is 40 amino acids in length and contains one tyrosine residue (Y281), which is phosphorylated after treatment of cells with pervanadate [3].

Biological context of C6orf21

• Interestingly, the type I transmembrane protein G6f was found to be specifically phosphorylated on Tyr-281 in response to platelet activation by CRP, providing a docking site for the adapter Grb2 [1].
• Antibody cross-linking of G6f expressed in K562 cells resulted in a transient phosphorylation of p42/44 MAP kinase (also known as extracellular-signal-regulated protein kinase-1/2; MAP stands for mitogen-activated protein) which could be prevented by MAP kinase kinase (MEK) inhibitors [3].

Other interactions of C6orf21

• Immunoprecipitation experiments showed the interaction of full-length phosphorylated G6f with both full-length Grb2 and Grb7 [3].

References