Objective: To review and summarize literature regarding stimulatory and inhibitory signaling pathways from different types of Fc gamma receptors (FcgammaRs).
Data source: Articles were obtained from Medline from January 1991 to April 2002.
Study selection: Over 100 English language papers and reviews published over the last 11 years were selected.
Results and conclusions: Stimulatory Fcgamma receptors include FcgammaRI, FcgammaRIIA, FcgammaRIIC, and FcgammaRIII A. They transduce signals through the immunoreceptor tyrosine-based activation motif (ITAM) in subunits or in the cytoplasmic domain. Inhibitory Fcgamma receptors, such as FcgammaRIIB, are single chain receptors, transducing signals through an immunoreceptor tyrosine-based inhibitory motif (ITIM) in cytoplasmic domains. Stimulatory signals include protein phosphorylation, increase in intracellular free calcium, the production of 1,4,5-triphosphate inositol (IP(3)) and diacylglycerol (DAG) mainly through the Src-family kinases, phosphoinositide 3-kinase (PI3-K) and phospholipase C (PLC). Inhibitory signaling has been implicated in the repression of the above activities as well as inhibition of B cell responses through Src homology 2-containing inositol phosphatase (SHIP).