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Titolo:
MANNOSE 6-PHOSPHATE RECEPTORS AND ADP-RIBOSYLATION FACTORS COOPERATE FOR HIGH-AFFINITY INTERACTION OF THE AP-1 GOLGI ASSEMBLY PROTEINS WITHMEMBRANES
Autore:
LEBORGNE R; GRIFFITHS G; HOFLACK B;
Indirizzi:
EUROPEAN MOLEC BIOL LAB,POSTFACH 102209 MEYERHOFSTR 1 D-69012 HEIDELBERG GERMANY EUROPEAN MOLEC BIOL LAB D-69012 HEIDELBERG GERMANY
Titolo Testata:
The Journal of biological chemistry
fascicolo: 4, volume: 271, anno: 1996,
pagine: 2162 - 2170
SICI:
0021-9258(1996)271:4<2162:M6RAAF>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
CLATHRIN-COATED PITS; GTP-BINDING PROTEIN; FACTOR-II RECEPTOR; BREFELDIN-A; GUANINE-NUCLEOTIDE; CYTOPLASMIC DOMAIN; VESICLE PROTEINS; INVITRO BINDING; 100-KD PROTEINS; ARF PROTEIN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
62
Recensione:
Indirizzi per estratti:
Citazione:
R. Leborgne et al., "MANNOSE 6-PHOSPHATE RECEPTORS AND ADP-RIBOSYLATION FACTORS COOPERATE FOR HIGH-AFFINITY INTERACTION OF THE AP-1 GOLGI ASSEMBLY PROTEINS WITHMEMBRANES", The Journal of biological chemistry, 271(4), 1996, pp. 2162-2170

Abstract

Clathrin coat assembly in the trans-Golgi network, leading to the sequestration of the mannose 6-phosphate receptors (MPRs) into nascent vesicles, requires the ARF-1-dependent translocation of the cytosolic AP-1 Golgi assembly proteins onto the membranes of this organelle. The mechanistic role of the MPRs, i.e. the cargo molecules, in coat assembly is at present unclear. Using a GTP-dependent, brefeldin A-sensitive in vitro AP-1 binding assay, we have determined here the parameters ofthe AP-1 binding reaction. We demonstrate that, in addition of ARF-1,the MPRs contribute to create high affinity AP-1 binding sites (K-d approximate to 25 nM), since their number correlates the number of MPR molecules expressed in MPR-negative cells. The quantitative electron microscopy shows that these high affinity binding sites are present on trans-Golgi network membranes, as expected, and to some extent on early endosomes. The high affinity binding sites are lost when the MPRs orARF-1 become rate-limiting components. Conversely, GTP gamma S (guanosine 5'-O-(3-triotriphosphate)), which increases the amount of membrane-bound ARF-1, mostly uncovers low affinity AP-1 binding sites (K-d approximate to 150 nM) on trans-Golgi network membranes, normally not detected in its absence. Collectively, these results argue that MPR sorting is highly coupled to the first step of coat assembly and that the MPRs, ARF-1, and possibly other proteins cooperate for high affinity interactions of AP-1.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/01/20 alle ore 01:30:15