Co-localization of a kallikrein-like serine protease (arginine esterase A) and atrial natriuretic peptide in rat atrium.
Atrial natriuretic peptide (ANP) is stored in atrial granules primarily as a larger molecular weight precursor (pro-ANP), which is believed to be rapidly converted to an active peptide of 28 amino acids during or shortly after secretion. A tissue kallikrein-like serine protease has been suggested as a potential processing enzyme. In the present immunocytochemical study, using specific monoclonal antibodies, we found that esterase A, a kallikrein-like serine protease, was demonstrable in rat atrial myocytes and in ventricular myocytes, and was capable of cleaving pro-ANP to yield a low molecular weight product. Using colloidal gold immunocytochemistry at the electron microscopic level, we have found esterase A in atrial myocytes, both in granules and in another subcellular site that corresponds to sarcoplasmic reticulum. Double-label electron microscopic immunocytochemical results indicated that esterase A can co-localize with ANP in granules of atrial myocytes.
Simson
J A
JA
Department of Anatomy, Medical University of South Carolina, Charleston 29425.
Currie
M G
MG
Chao
L
L
Chao
J
J
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000378:metabolism; D006325:Heart Atria / Q000378:metabolism*; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D011499:Protein Processing, Post-Translational; D051381:Rats
D009320:Atrial Natriuretic Factor; C019724:arginine esterase; D002265:Carboxylic Ester Hydrolases