TY - JOUR
T1 - Neutral ceramidase secreted by endothelial cells is released in part associated with caveolin-1
AU - Romiti, Elena
AU - Meacci, Elisabetta
AU - Donati, Chiara
AU - Formigli, Lucia
AU - Zecchi-Orlandini, Sandra
AU - Farnararo, Marta
AU - Ito, Makoto
AU - Bruni, Paola
N1 - Funding Information:
This work was supported by funds from the Cofinanziamento Ministero dell’Università e della Ricerca Scientifica e Tecnologica (MURST) Progetti di Interesse Nazionale (PRIN) 1999 and from Ente Cassa di Risparmio di Firenze (to M.F.). We thank Daniele Nosi for image processing.
PY - 2003/9/1
Y1 - 2003/9/1
N2 - Neutral ceramidase (CDase) is a key enzyme of sphingomyelin (SM) metabolism implicated in cell signaling triggered by a variety of extracellular ligands. Previously it was shown that in murine endothelial cells a portion of neutral CDase is localized in detergent-resistant light membranes. In this study subcellular distribution of neutral CDase was further investigated. In accordance with the previous finding, the enzyme was identified in caveolae. Moreover, the same protein was detected in medium-speed supernatant of cell-conditioned medium, accounting for CDase activity measurable in the medium at neutral pH. Notably, these cells released also the caveolae-scaffolding protein caveolin-1 (cav-1). Interestingly, secreted neutral CDase and cav-1 coimmunoprecipitated. In addition, acid sphingomyelinase (SMase) activity was detectable in cav-1 immunocomplexes. These findings are consistent with the view that neutral CDase is released, in part, in association with cav-1 together with acid SMase. It remains to be established whether the here-identified secreted cav-1-enriched complex acts as platform to facilitate extracellular metabolism of SM.
AB - Neutral ceramidase (CDase) is a key enzyme of sphingomyelin (SM) metabolism implicated in cell signaling triggered by a variety of extracellular ligands. Previously it was shown that in murine endothelial cells a portion of neutral CDase is localized in detergent-resistant light membranes. In this study subcellular distribution of neutral CDase was further investigated. In accordance with the previous finding, the enzyme was identified in caveolae. Moreover, the same protein was detected in medium-speed supernatant of cell-conditioned medium, accounting for CDase activity measurable in the medium at neutral pH. Notably, these cells released also the caveolae-scaffolding protein caveolin-1 (cav-1). Interestingly, secreted neutral CDase and cav-1 coimmunoprecipitated. In addition, acid sphingomyelinase (SMase) activity was detectable in cav-1 immunocomplexes. These findings are consistent with the view that neutral CDase is released, in part, in association with cav-1 together with acid SMase. It remains to be established whether the here-identified secreted cav-1-enriched complex acts as platform to facilitate extracellular metabolism of SM.
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U2 - 10.1016/S0003-9861(03)00212-1
DO - 10.1016/S0003-9861(03)00212-1
M3 - Article
C2 - 12921776
AN - SCOPUS:0043063958
SN - 0003-9861
VL - 417
SP - 27
EP - 33
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 1
ER -