title: Active caspase-3 is removed from cells by release of caspase-3-enriched vesicles.
abstract: Cleavage of Rho associated Coiled Coil kinase I (ROCK I) by caspase-3 contributes to membrane blebbing. Whether caspase-3 and ROCK I also play a role in the release of membrane vesicles is unknown. Therefore, we transfected a human breast cancer cell line (MCF-7) that is caspase-3 deficient, lacks membrane blebbing, and does not release membrane vesicles, with caspase-3. Cells expressing caspase-3 demonstrate both ROCK I-mediated membrane blebbing, and release of small (400-600nm) membrane vesicles in a ROCK I-independent manner. These membrane vesicles contain caspase-3, and are enriched in caspase-3 activity compared to the releasing cells. Caspase-3-containing vesicles are taken up by untransfected cells but the cells do not show any sign of apoptosis. In conclusion, we show that the release of caspase-3-enriched membrane vesicles and membrane blebbing are two differentially regulated processes. Furthermore, we hypothesize that packaging of caspase-3 into membrane vesicles contributes to cellular homeostasis by the removal of caspase-3, and concurrently, protects the cells' environment from direct exposure to caspase-3 activity.
authors.affiliation: Department of Clinical Chemistry, Academic Medical Center, Amsterdam, The Netherlands. A.N.Boing@amc.nl
authors.forename: A N
authors.initials: AN
authors.lastname: Böing
authors.forename: J
authors.initials: J
authors.lastname: Stap
authors.forename: C M
authors.initials: CM
authors.lastname: Hau
authors.forename: G B
authors.initials: GB
authors.lastname: Afink
authors.forename: C
authors.initials: C
authors.lastname: Ris-Stalpers
authors.forename: E A
authors.initials: EA
authors.lastname: Reits
authors.forename: A
authors.initials: A
authors.lastname: Sturk
authors.forename: C J F
authors.initials: CJ
authors.lastname: van Noorden
authors.forename: R
authors.initials: R
authors.lastname: Nieuwland
mesh_terms: D017209:Apoptosis / Q000502:physiology; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D061986:MCF-7 Cells; D022142:Secretory Vesicles / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D054460:rho-Associated Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: C515851:ROCK1 protein, human; D054460:rho-Associated Kinases; D053148:Caspase 3