Work

Distinct Roles of N-Glycosylation at Different Sites of Corin in Cell Membrane Targeting and Ectodomain Shedding

Year: 2014

Type: article

Abstract: Corin is a membrane-bound protease essential for activating natriuretic peptides and regulating blood pressure. Human corin has 19 predicted N -glycosylation sites in its extracellular domains. It has been shown that N -glycans are required for corin cell surface expression and zymogen activation. It remains unknown, however, how N -glycans at different sites may regulate corin biosynthesis and processing. In this study, we examined corin mutants, in which each of the 19 predicted N -glycosylation sites was mutated individually. By Western analysis of corin proteins in cell lysate and conditioned medium from transfected HEK293 cells and HL-1 cardiomyocytes, we found that N -glycosylation at Asn-80 inhibited corin shedding in the juxtamembrane domain. Similarly, N -glycosylation at Asn-231 protected corin from autocleavage in the frizzled-1 domain. Moreover, N -glycosylation at Asn-697 in the scavenger receptor domain and at Asn-1022 in the protease domain is important for corin cell surface targeting and zymogen activation. We also found that the location of the N -glycosylation site in the protease domain was not critical. N -Glycosylation at Asn-1022 may be switched to different sites to promote corin zymogen activation. Together, our results show that N -glycans at different sites may play distinct roles in regulating the cell membrane targeting, zymogen activation, and ectodomain shedding of corin.Corin is a transmembrane protease containing 19 predicted N -glycosylation sites. Results Corin mutants lacking individual N -glycosylation sites were studied for their biosynthesis and processing. Conclusion N -Glycosylation at different sites plays distinct roles in preventing ectodomain shedding and promoting cell surface targeting and zymogen activation. Significance The results are important for understanding how corin expression and activity are regulated.

Source: Journal of Biological Chemistry

DOI: 10.1074/jbc.m114.606442