title: Acid-activated prorenin binds to (pro)renin receptor in vitro.
abstract: Binding properties of acid-activated prorenin to (pro)renin receptor [(P)RR] was investigated in vitro to discuss possible roles of such reversibly acid-activated prorenin in the renin angiotensin (RA) system. Prorenin was acidified at pH 3.3, 4.5, 5.5, 6.5, and its activation level was measured at 1, 2, 4, 8, 12, and 25 h. Prorenin, activated non-proteolytically in time- and pH-dependent manners, was verified by Western blot analyses. Acidification of prorenin for 25 h at pH 3.3, 4.5, 5.5, and 6.5 showed 78%, 54%, 34%, and 20% activities, respectively when compared with the renin activity of trypsinized prorenin as 100%. Additionally, the binding properties of acidified prorenin to (P)RR were elucidated both at the equilibrium state and in the kinetic state using BIAcore. BIAcore assay showed that acidified prorenin at pH 3.3, 4.5, 5.5, and 6.5 had apparent K(D) of 1.57 × 10(4), 14.1, 8.29, and 8.04 nM, respectively while native prorenin at pH 7.4 had a K(D) of 7.8 nM. At equilibrium state, K(D) of native prorenin was 1.42 nM whereas apparent K(D) varied from 1.25 to 5.0 nM for the prorenin acidified at pH 4.5, 5.5, and 6.5. The K(m) values of free forms of acidified prorenin at different pH (0.33-0.5 μM) was almost similar to those of (P)RR-bound forms of acidified prorenin (0.5-0.77 μM). These in vitro data indicate that prorenin acidified in vivo possibly modulate RA system in receptor-dependent and/or -independent manners which could ultimately lead to the pathogenesis of diseases.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh.
authors.forename: A H M Nurun
authors.initials: AH
authors.lastname: Nabi
authors.forename: Kazal Boron
authors.initials: KB
authors.lastname: Biswas
authors.forename: K M Nasrin
authors.initials: KM
authors.lastname: Haque
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Arai
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Akio
authors.initials: A
authors.lastname: Ebihara
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Ichihara
authors.forename: Tadashi
authors.initials: T
authors.lastname: Inagami
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Suzuki
mesh_terms: D000143:Acids / Q000737:chemistry*; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D006801:Humans; D006863:Hydrogen-Ion Concentration; D055767:Immobilized Proteins; D007700:Kinetics; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D012083:Renin / Q000737:chemistry*; D020349:Surface Plasmon Resonance; D000093342:Prorenin Receptor
chemical_list: D000143:Acids; D055767:Immobilized Proteins; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D012083:Renin; D000093342:Prorenin Receptor