CHARACTERIZATION OF ATRIAL-NATRIURETIC-FACTOR RECEPTORS IN ADRENAL-CORTEX, VASCULAR SMOOTH-MUSCLE AND ENDOTHELIAL-CELLS BY AFFINITY LABELING

The structural homologies among the receptors for atrial natriuretic factor (ANF) in different tissues and species have been examined by affinity labeling. Membrane preparations from bovine adrenal cortex, rat aortic smooth muscle cells and bovine carotid endothelial cells were incubated with 125I-ANF and the bound 125I-ANF was covalently cross-linked to the receptor with disuccinimidyl suberate. Analysis of the labeled products by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography revealed that 125I-ANF interacts with a 140-kDa membrane component of these target tissues. The apparent Mr of the labeled species was reduced to 70,000 by treatment with 2-mercaptoethanol. These results indicate that ANF receptors in the adrenal gland and vascular tissues are of nearly identical size (Mr, .apprx. 140,000) and contain a 70-kDa ANF-binding subunit linked to the other components of the receptor by interchain disulfide bond(s).