Receptor/ligand binding autocrine growth factor

Antibodies that can block the biological activities of growth factor receptors are expected to alter the autocrine and paracrine loops. The rationale that specific ligand binding inhibition can decrease the mitogenic signaling... 

LPA can transactivate the epidermal growth factor receptor (EGFR), i.e. induce the tyrosine phosphorylation and activation of EGFR in the absence of EGF addition (Daub et al, 1996). This occurs due to the autocrine or paracrine action of heparin-binding EGF (an EGF receptor ligand) that is constitutively shed in the presence of LPA (Hirata et al., 2001). However, LPA-stimulated p42/p44 MAPK activation can also occur entirely independently of the EGF receptor (Andreev et al, 2001). 

---