Figure 3.

FcγRIIA-induced platelet activation and signaling pathways. IgG antibodies or larger immune complexes can activate platelets by dimerization or clustering of FcγRIIA receptors. The tyrosine-based activation motif (ITAM) is then phosphorylated by Src-family kinases (SFK), recruiting and phosphorylating the tyrosine kinase Syk, which in turn activates phosphoinositide 3-kinase (PI3K). The production of phosphatidylinositol-3,4,5-trisphosphate (PIP₃) recruits Bruton’s tyrosine kinase (BTK) and phospholipase Cγ (PLCγ), which leads to activation of downstream responses via IP₃ production and protein kinase C (PKC). The extent of platelet activation is likely dependent on the type of IgG antibodies and immune complexes. Created with BioRender.com.