Functions of Tec family kinases Tec family kinases are involved in the intracellular signaling mechanisms of
cytokine receptors, lymphocyte surface
antigens,
heterotrimeric G-protein-coupled receptors, and
integrin molecules. They are also key players in the regulation of the immune functions.
Functions of Tec kinase Lymphoid Cells Tec kinase has low expression in
naïve T cells but is upregulated upon
T-cell activation, especially in the presence of TGF-ß1 and
IL-6.
Myeloid Cells Tec kinase plays a role in the
toll-like receptor (TLR) signaling pathway of
macrophages that produces
pro-inflammatory cytokines TNF-α and
IL-6. Btk has an important function in this pathway, as it has been observed to bind to
TLR4,
MyD88, and
IRAK-1 signaling proteins. Tec kinase is likely involved in the same manner in macrophages, as it has a compensatory function for Btk. Tec kinase is activated in
platelets upon platelet stimulation with
thrombin or
collagen. Tec kinase is involved in the regulation of
PLCγ2 activation, platelet aggregation, and spreading
GPVI collagen receptor. Btk plays a more important role in these processes, but Tec kinase is able to compensate for loss of Btk in
XLA immune-deficient patients. Patients deficient in both Btk and Tec kinase display greatly impaired phosphorylation of PLCγ2, no aggregation of platelets in response to high doses of collagen, and greatly impaired spreading of collagen. Tec kinase is activated in
neutrophils upon neutrophil stimulation with chemoattractant
fMLP. It is not clear what the function of Tec kinase is in neutrophils. Tec kinase is also expressed in primary
mast cells and
erythroid cells. Its function has not been identified in these cells. == Activation ==