Intracellular retention of the corticotrophin-releasing hormone (CRH) precursor within COS-7 cells

PERONE, MJ; WINDEATT, S; MORRISON, E; SHERING, A; TOMASEC, P; LINTON, EA; LOWENSTEIN, PR; CASTRO, MG

THE JOURNAL OF HISTOCHEMISTRY AND CYTOCHEMISTRY : OFFICIAL JOURNAL OF THE HISTOCHEMISTRY SOCIETY.

HISTOCHEMICAL SOC INC

Año: 1998

0022-1554

We investigated the intracellular localization of CRH in transiently transfectedCOS-7 cells expressing the full-length rat corticotropin-releasing hormone (CRH) precursorcDNA. CRH synthesized by transfected COS-7 cells is mainly stored intracellularly. Incontrast, CHO-K1 cells expressing the same CRH precursor stored and released equalamounts of immunoreactive (IR)-CRH. Ultrastructural analysis revealed that CRH is stored inelectron-dense aggregates in the RER of transiently transfected COS-7 cells and does notmigrate into the Golgi apparatus. On the basis of the different intracellular localization,storage, and release of CRH in COS-7 and CHO-K1 cells, we hypothesize that the intracellulartrafficking of CRH within the constitutive secretory pathway for protein secretion notonly depends on its primary amino acid sequence but might also be influenced by intracellularconditions or factors.