Syk

Syk (Spleen tyrosine kinase) is a cytosolic non-receptor protein tyrosine kinase (PTK) that is expressed at high levels, both in hematopoietic cells (such as mast cells, B lymphocytes, T lymphocytes, neutrophils, dendritic cells, and macrophages) and in non-hematopoietic cells.

Syk mediates key signal transduction pathways following the activation of immune cell receptors. Syk associates with different receptors on the surface of various cells such as B cells, mast cells, monocytes, macrophages, and neutrophils, and even osteoclasts and breast cancer cells. Following the engagement of these receptors with their ligands, SYK is activated and orchestrates diverse cellular responses, including cytokine production (in T cells and monocytes) and phagocytosis (in macrophages).