protein tyrosine kinase 2 (PTK2) plays an essential role in regulating cell migration, adhesion, spreading, reorganization of the actin cytoskeleton, formation and disassembly of focal adhesions and cell protrusions, cell cycle progression, cell proliferation and apoptosis. Required for early embryonic development and placenta development. PTK2 regulates numerous signaling pathways. It promotes activation of phosphatidylinositol 3-kinase and the AKT1 signaling cascade as well as activation of MAPK1/ERK2, MAPK3/ERK1 and the MAP kinase signaling cascade. It promotes localized and transient activation of guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs), and thereby modulates the activity of Rho family GTPases. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804