Spleen tyrosine kinase (Syk) is a cytosolic non-receptor protein tyrosine kinase (PTK). Syk contains two N-terminal SH2 domains and one Cterminal tyrosine kinase domain. The SH2 domains of Syk bind to immunoreceptor tyrosine-based activation motifs (ITAMs), leading to Syk activation. Syk protein lacks myristoylation site, therefore does not attach directly to the cell membrane.Syk was recognized as a critical element in the BCR signaling pathway. Syk along with other BCR signaling molecules, Bruton tyrosine kinase (BTK), PI3K delta (PI3Kδ), and tumor necrosis factor (TNF) superfamily receptors was also found to be involved in signal transduction independent from the BCR. Syk is expressed primarily in hematopoietic cells like Bcells, monocytes, macrophages, mast cells, and neutrophils. Syk was recognized to be a potential target for the treatment of various hematologic cancers, autoimmune disorders, and other inflammatory states.


1.Liu D,et al. J Hematol Oncol. 2017;10(1):145.