title: Calpain-1 resident in lipid raft/caveolin-1 membrane microdomains plays a protective role in endothelial cells.
abstract: We are here reporting that calpain-1 is a constitutive component of a distinct lipid raft/caveolin-1 microdomain isolated from bEnd5 cells in association with endothelial nitric oxide synthase (eNOS) and heat shock protein 90 (HSP90). Perturbations in intracellular calcium concentration by Ca2+-ionophore A23187 or prolonged cell exposure to high glucose induce a significant decrease in the level of eNOS accompanied by a recruitment of additional HSP90 molecules at this site. In these conditions the cells are more resistant to cell death by Ca2+overload. The decrease of eNOS has been due not only to its Ca2+-mediated release from the caveolin-1 aggregates but also to its digestion by calpain-1. The specific involvement of calpain-1 in digestion of eNOS is supported by the preventive effect of a synthetic calpain inhibitor (CI-2) and by the absence of calpain-2 and calpastatin in the caveolin-1 microdomain. These results suggest that the protein adjustments observed in lipid raft/caveolin-1 microdomains could be visualized as a process required to protect the cells against NO overproduction and aberrant calpain activation. Alterations in eNOS, calpain-1 and HSP90 levels have been observed in aorta of Zucker Diabetic Rats (ZDR). The loss of HSP90 occurring in these animals indicates an aberrant activation of calpain and thereby the transition from a physiological to a pathological cell condition.
authors.affiliation: Department of Experimental Medicine (DIMES) - Biochemistry Section, University of Genova, Viale Benedetto XV, 1, 16132 Genova, Italy.
authors.forename: Antonino
authors.initials: A
authors.lastname: Martines
authors.affiliation: National Research Council (CNR), Institute of Marine Sciences (ISMAR), U.O.S. of Genoa, Via De Marini, 6, 16149 Genoa, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Stifanese
authors.affiliation: Department of Experimental Medicine (DIMES), Section of Human Physiology, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy.
authors.forename: Emanuela L
authors.initials: EL
authors.lastname: Faelli
authors.affiliation: Department of Experimental Medicine (DIMES), Section of Human Physiology, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Perasso
authors.affiliation: Department of Neurosurgery, San Martino IST University Hospital (IRCCS), Largo Rosanna Benzi 10, 16132, Genova, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Melloni
authors.affiliation: Department of Experimental Medicine (DIMES), Section of Human Physiology, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Ruggeri
authors.affiliation: Department of Experimental Medicine (DIMES) - Biochemistry Section, University of Genova, Viale Benedetto XV, 1, 16132 Genova, Italy. Electronic address: monica.averna@unige.it.
authors.forename: Monica
authors.initials: M
authors.lastname: Averna
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism / Q000473:pathology; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000737:chemistry / Q000378:metabolism*; D051242:Caveolin 1 / Q000737:chemistry / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000737:chemistry / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000737:chemistry / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D059748:Proteolysis; D051381:Rats
chemical_list: D051242:Caveolin 1; D018841:HSP90 Heat-Shock Proteins; D009842:Oligopeptides; D009569:Nitric Oxide; C047473:N-(3-N-(benzyloxycarbonyl)amino-1-carboxypropyl)leucyl-O-methyltyrosine N-methylamide; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; D002154:Calpain; D002118:Calcium
keywords: Ca(2+)-dependent proteolysis; Calpain; Diabetes; HSP90; eNOS; nNOS