FGR Protein, Human (Active, sf9, GST)

FGR Protein, a non-receptor tyrosine-protein kinase, serves as a pivotal mediator in immune regulation across various cell types, including neutrophils, monocytes, macrophages, and mast cells. It facilitates signal transmission from cell surface receptors lacking kinase activity, orchestrating essential cellular functions such as cytoskeleton remodeling, phagocytosis, cell adhesion, and migration. Functionally versatile, FGR Protein acts downstream of receptors binding the Fc region of immunoglobulins (MS4A2/FCER1B, FCGR2A, and/or FCGR2B), as well as ITGB1 and ITGB2, finely tuning actin cytoskeleton organization, cell spreading, and adhesion. Its role is context-dependent, either activating or inhibiting cellular responses. Notably, in monocytes, FGR Protein acts as a negative regulator, dampening ITGB2 signaling, phagocytosis, and SYK activity. Furthermore, it is indispensable for normal ITGB1 and ITGB2 signaling, maintaining typical cell spreading and adhesion in neutrophils and macrophages. FGR Protein positively influences cell migration, directing cytoskeleton reorganization through RAC1 activation. It engages in phosphorylation events, impacting pathways involving SYK, PLD2, AKT1, MAP kinase, PIK3R1, FASLG, ABL1, CBL, CTTN, PTK2/FAK1, PTK2B/PYK2, and VAV2. Additionally, in collaboration with CLNK, it acts as a negative regulator of natural killer cell-activating receptors, thereby suppressing interferon-gamma production.