Hayer, Arnold; Stöber, Miriam; Ritz, Danilo; Engel, Sabrina; Meyer, Hemmo; Helenius, Ari:

Caveolin-1 is ubiquitinated and targeted to intralumenal vesicles in endolysosomes for degradation

In: Journal of Cell Biology, Jg. 191 (2010) ; Nr. 3, S. 615-629
ISSN: 0021-9525
Zeitschriftenaufsatz / Fach: Biologie
Fakultät für Biologie » Chemische Biologie
Abstract:
5Caveolae are long-lived plasma membrane micro domains composed of
   caveolins, cams, and a cholesterol-rich membrane Little is known about
   how caveolae disassemble and how their coat components are degraded We
   studied the degradation of caveolin 1 (CAV1), a map caveolar protein, in
   CV1 cells CAV1 was degraded very slowly, but turnover could be
   accelerated by compromising caveolae assembly Now, CAV1 became
   detectable in late endosomes (LE) and lysosomes where it was degraded
   Targeting to the degradative pathway required ubiquitination and the
   endosomal sorting complex required for transport (ESCRT) machinery for
   inclusion into intralumenal vesicles in endosomes A dual-tag strategy
   allowed us to monitor exposure of CAV1 to the acidic lumen of
   individual, maturing LE in living cells Importantly, we found that
   "caveosomes," previously described by our group as independent or
   ganelles distinct from endosomes, actually correspond to late endosomal
   compartments modified by the accumulation of overexpressed CAV1 awaiting
   degradation The findings led us to a revised model for endocytic
   trafficking of CAV1