Tyrosine-protein kinase that acts downstream of cell surface receptors for growth factors and plays a role in the regulation of the actin cytoskeleton, microtubule assembly, lamellipodia formation, cell attachment and cell migration. Acts downstream of EGFR, PDGFRA and PDGFRB. Acts downstream of EGFR to promote activation of NF-kappa-B and cell proliferation. Acts downstream of the activated FCER1 receptor and plays a role in FCER1 (high affinity immunoglobulin epsilon receptor)-mediated signaling in mast cells. Plays a role in the regulation of mast cell degranulation. Phosphorylates CTTN, CTNND1, PTK2/FAK1, GAB1, PECAM1 and PTPN11 (By similarity). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Homotrimer. Interacts with CTNND1, EGFR, FLT3, IRS1, PECAM1, PIK3R1 and PDGFR. Interacts (via SH2 domain) with CTTN. Component of a complex that contains at least FER, CTTN and PTK2/FAK1 (By similarity). Associated with the chromatin. Detected on microtubules in polarized and motile vascular endothelial cells. Colocalizes with F-actin at the cell cortex. Colocalizes with PECAM1 and CTNND1 at nascent cell-cell contacts (By similarity). The coiled coil domains mediate homooligomerization and are required for location at microtubules. The N-terminal region including the first coiled coil domain mediates interaction with phosphoinositide-containing membranes. Autophosphorylated. Belongs to the protein kinase superfamily. Tyr protein kinase family. Fes/fps subfamily.