Platelet Derived Growth Factor Receptor (PDGFR) is a cell surface tyrosine kinase receptor that is activated by binding to the Platelet Derived Growth Factor (PDGF). It plays a crucial role in various cellular processes including growth, differentiation, and proliferation. PDGFR exists in two isoforms, PDGFR-alpha and PDGFR-beta, each with distinct ligand-binding specificities and biological functions.