FYN

FYN (proto-oncogene tyrosine-protein kinase Fyn), also designated SLK or SYN, is a Src-family non-receptor tyrosine kinase regulating diverse cellular processes through phosphorylation-mediated signaling. It interacts with scaffolding adaptors like PAG/Cbp to modulate T-cell receptor activation and integrin-mediated adhesion via downstream effectors including FAK and paxillin. FYN participates in critical pathways such as B-cell receptor signaling, Wnt/β-catenin modulation, and NMDA receptor trafficking in neurons. Aberrant FYN activity is implicated in Alzheimer's disease through Tau protein hyperphosphorylation, multiple sclerosis via immune cell dysregulation, and malignancies like glioblastoma and hormone-resistant prostate cancers. While pan-Src kinase inhibitors (e.g., dasatinib) show partial FYN inhibition, selective FYN-targeted therapies remain investigational. Recent preclinical efforts focus on disrupting FYN's SH3 domain interactions and its synergistic role with EGFR/PDGFR in tumor invasiveness.