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Titolo:
Localization and recycling of gp27 (hp24 gamma(3)): Complex formation withother p24 family members
Autore:
Fullekrug, J; Suganuma, T; Tang, BL; Hong, WJ; Storrie, B; Nilsson, T;
Indirizzi:
European,Mol Biol Lab, Cell Biol & Cell Biophys Program, D-69117 Heidelberg European Mol Biol Lab Heidelberg Germany D-69117 ram, D-69117 Heidelberg Miyazaki Med Coll, Dept Anat, Miyazaki 8891692, Japan Miyazaki Med Coll Miyazaki Japan 8891692 t Anat, Miyazaki 8891692, Japan Inst Mol & Cell Biol, Membrane Biol Lab, Singapore 117609, Singapore Inst Mol & Cell Biol Singapore Singapore 117609 gapore 117609, Singapore Virginia Polytech Inst & State Univ, Dept Biochem, Blacksburg, VA 24061 USA Virginia Polytech Inst & State Univ Blacksburg VA USA 24061 VA 24061 USA
Titolo Testata:
MOLECULAR BIOLOGY OF THE CELL
fascicolo: 6, volume: 10, anno: 1999,
pagine: 1939 - 1955
SICI:
1059-1524(199906)10:6<1939:LAROG(>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
COPII-COATED VESICLES; TO-GOLGI TRANSPORT; ENDOPLASMIC-RETICULUM; PROTEIN-TRANSPORT; INTERMEDIATE COMPARTMENT; TRANSMEMBRANE PROTEIN; MAMMALIAN-CELLS; LIVING CELLS; HELA-CELLS; APPARATUS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
37
Recensione:
Indirizzi per estratti:
Indirizzo: Nilsson, T European,Mol Biol Lab, Cell Biol & Cell Biophys Program, D-69117 Heidelberg European Mol Biol Lab Heidelberg Germany D-69117 7 Heidelberg
Citazione:
J. Fullekrug et al., "Localization and recycling of gp27 (hp24 gamma(3)): Complex formation withother p24 family members", MOL BIOL CE, 10(6), 1999, pp. 1939-1955

Abstract

We report here the characterization of gp27 (hp24 gamma(3)), a glycoprotein of the p24 family of small and abundant transmembrane proteins of the secretory pathway. Immunoelectron and confocal scanning microscopy show that at steady state, gp27 localizes to the cis side of the Golgi apparatus. In addition, some gp27 was detected in COPI- and COPII-coated structures throughout the cytoplasm. This indicated cycling that was confirmed in three ways. First, 15 degrees C temperature treatment resulted in accumulation of similar to p27 in pre-Golgi structures colocalizing with anterograde cargo. Second, treatment with brefeldin A caused gp27 to relocate into peripheral structures positive for both KDEL receptor and COPII. Third, microinjection of a dominant negative mutant of Sar1p trapped gp27 in the endoplasmic reticulum (ER) by blocking ER export. Together, this shows that gp27 cycles extensively in the early secretory pathway. Immunoprecipitation and coexpression studies further revealed that a significant fraction of gp27 existed in ahetero-oligomeric complex. Three members of the p24 family, GMP25 (hp24 alpha(2)), p24 (hp24 beta(1)), and p23 (hp24 delta(1)), coprecipitated in what appeared to be stochiometric amounts. This heterocomplex was specific. Immunoprecipitation of p26 (hp24 gamma(4)) failed to coprecipitate GMP25, p24, or p23. Also, very little p26 was found coprecipitating with gp27. A functional requirement for complex formation was suggested at the level of ER export. Transiently expressed gp27 failed to leave the ER unless other p24 family proteins were coexpressed. Comparison of attached oligosaccharides showed that gp27 and GMP25 recycled differentially. Only a very minor portionof GMP25 displayed complex oligosaccharides. In contrast, all of gp27 showed modifications by medial and trans enzymes at steady state. We conclude from these data that a portion of gp27 exists as hetero-oligomeric complexeswith GMP25, p24, and p23 and that these complexes are in dynamic equilibrium with individual p24 proteins to allow for differential recycling and distributions.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 09:45:21