A familial mutation renders atrial natriuretic Peptide resistant to proteolytic degradation.
A heterozygous frameshift mutation causing a 12-amino acid extension to the C terminus of atrial natriuretic peptide (ANP) was recently genetically linked to patients with familial atrial fibrillation (Hodgson-Zingman, D. M., Karst, M. L., Zingman, L. V., Heublein, D. M., Darbar, D., Herron, K. J., Ballew, J. D., de Andrade, M., Burnett, J. C., Jr., and Olson, T. M. (2008) N. Engl. J. Med. 359, 158-165). The frameshift product (fsANP), but not wild-type ANP (wtANP), was elevated in the serum of affected patients, but the molecular basis for the elevated peptide concentrations was not determined. Here, we measured the ability of fsANP to interact with natriuretic peptide receptors and to be proteolytically degraded. fsANP and wtANP bound and activated human NPR-A and NPR-C similarly, whereas fsANP had a slightly increased efficacy for human NPR-B. Proteolytic susceptibility was addressed with novel bioassays that measure the time required for kidney membranes or purified neutral endopeptidase to abolish ANP-dependent activation of NPR-A. The half-life of fsANP was markedly greater than that of wtANP in both assays. Additional membrane proteolysis studies indicated that wtANP and fsANP are preferentially degraded by neutral endopeptidase and serine peptidases, respectively. These data indicate that the familial ANP mutation associated with atrial fibrillation has only minor effects on natriuretic peptide receptor interactions but markedly modifies peptide proteolysis.
Dickey
Deborah M
DM
Departments of Biochemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Yoder
Andrea R
AR
Potter
Lincoln R
LR
D000595:Amino Acid Sequence; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D001667:Binding, Competitive; D002460:Cell Line; D006152:Cyclic GMP / Q000378:metabolism; D005192:Family Health; D006801:Humans; D006868:Hydrolysis; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000097:blood / Q000378:metabolism*; D009154:Mutation; D015260:Neprilysin / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000378:metabolism; D000099242:Atrial Natriuretic Factor Receptor B
D009320:Atrial Natriuretic Factor; D006152:Cyclic GMP; D050505:Mutant Proteins; D015260:Neprilysin; D017461:Receptors, Atrial Natriuretic Factor; D012697:Serine Endopeptidases; D000099242:Atrial Natriuretic Factor Receptor B; C091715:atrial natriuretic factor receptor A; C073616:atrial natriuretic factor receptor C