Cloning and characterization of an endogenous COS-7 cell thromboxane A2 receptor.

A cDNA for a thromboxane A2 (TXA2) receptor was cloned from an SV40 transformed African Green Monkey kidney cell line (COS-7). The sequence is 98% homologous with the isoform of the human TXA2 receptor and has agonist and antagonist ligand binding characteristics that are not significantly different from the human receptor. Stimulation of the COS-7 cells with the TXA2 receptor agonist, ONO 11113 resulted in a significant increase in cAMP formation that was blocked by a receptor antagonist. The results raise the question of the utility of the COS-7 cell line for studies of cloned and expressed TXA2 receptor signalling mechanisms.