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Titolo:
Toxoplasma gondii ADP-ribosylation factor 1 mediates enhanced release of constitutively secreted dense granule proteins
Autore:
Liendo, A; Stedman, TT; Ngo, HM; Chaturvedi, S; Hoppe, HC; Joiner, KA;
Indirizzi:
Yale Univ, Sch Med, Dept Internal Med, Sect Infect Dis,LCI 808, New Haven,CT 06520 USA Yale Univ New Haven CT USA 06520 fect Dis,LCI 808, New Haven,CT 06520 USA
Titolo Testata:
JOURNAL OF BIOLOGICAL CHEMISTRY
fascicolo: 21, volume: 276, anno: 2001,
pagine: 18272 - 18281
SICI:
0021-9258(20010525)276:21<18272:TGAF1M>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
GTP-BINDING PROTEIN; PANCREATIC BETA-CELLS; COP-COATED VESICLES; PHOSPHOLIPASE-D; GOLGI MEMBRANES; REGULATED EXOCYTOSIS; MICRONEME DISCHARGE; PLASMA-MEMBRANE; ADAPTER COMPLEX; PC12 CELLS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Joiner, KA Yale Univ, Sch Med, Dept Internal Med, Sect Infect Dis,LCI 808,333 Cedar St, New Haven, CT 06520 USA Yale Univ 333 Cedar St New Haven CT USA 06520 ven, CT 06520 USA
Citazione:
A. Liendo et al., "Toxoplasma gondii ADP-ribosylation factor 1 mediates enhanced release of constitutively secreted dense granule proteins", J BIOL CHEM, 276(21), 2001, pp. 18272-18281

Abstract

Toxoplasma gondii dense granules are morphologically similar to dense matrix granules in specialized secretory cells, yet are secreted in a constitutive, calcium-independent fashion. We previously demonstrated that secretionof dense granule proteins in permeabilized parasites was augmented by the non-hydrolyzable GTP analogue guanosine 5'-3-O-(thio)triphosphate (GTP gammaS) (Chaturvedi, S., Qi, H., Coleman, D. L., Hanson, P., Rodriguez, A., andJoiner, K. A (1998) J. Biol. Chem. 274, 2424-2431). As now demonstrated bypharmacological and electron microscopic approaches, GTP gammaS enhanced release of dense granule proteins in the permeabilized cell system. To investigate the role of ADP-ribosylation factor 1 (ARF1) in this process, a cDNAencoding T. gondii ARF1 (TgARF1) was isolated. Endogenous and transgenic TgARF1 localized to the Golgi of T. gondii, but not to dense granules. An epitope-tagged mutant of TgARF1 predicted to be impaired in GTP hydrolysis (Q71L) partially dispersed the Golgi signal, with localization to scattered vesicles, whereas a mutant impaired in nucleotide binding (T31N) was cytosolic in location. Both mutants caused partial dispersion of a Golgi/trans-Golgi network marker. TgARF1 mutants inhibited delivery of the secretory reporter, Escherichia coil alkaline phosphatase, to dense granules, precluding an in vivo assessment of the role of TgARF1 in release of intact dense granules. To circumvent this limitation, recombinant TgARF1 was purified using two separate approaches, and used in the permeabilized cell assay. TgARF1 protein purified on a Cibacron G3 column and able to bind GTP stimulated dense granule secretion in the permeabilized cell secretion assay. These results are the first to show that ARF1 can augment release of constitutively secreted vesicles at the target membrane.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 10:03:46