INVESTIGADORES
ALVAREZ Cecilia Ines
artículos
Título:
Rab1b Interacts with GBF1, Modulates both ARF1 Dynamics and COPI Association
Autor/es:
1. PABLO MONETTA, ILEANA SLAVIN, NAHUEL ROMERO, CECILIA ALVAREZ
Revista:
MOLECULAR BIOLOGY OF THE CELL
Editorial:
American Society for Cell Biology
Referencias:
Lugar: Bethesda, MD; Año: 2007 vol. 18 p. 2400 - 2410
ISSN:
1059-1524
Resumen:
Assembly of the cytosolic coat protein I (COPI) complex at the ERGolgi interface is directed by the ADP ribosylation
factor1 (Arf1) and its guanine nucleotide exchange factor (GBF1). Rab1b GTPase modulates COPI recruitment, but the
molecular mechanism underlying this action remains unclear. Our data reveal that in vivo expression of the GTPrestricted
Rab1b mutant (Rab1Q67L) increased the association of GBF1 and COPI to peripheral structures localized at the
ER exit sites (ERES) interface. Active Rab1b also stabilized Arf1 on Golgi membranes. Furthermore, we characterized
GBF1 as a new Rab1b effector, and showed that its N-terminal domain was involved in this interaction. Rab1b small
interfering RNA oligonucleotide assays suggested that Rab1b was required for GBF1 membrane association. To further
understand how Rab1b functions in ER-to-Golgi transport, we analyzed GFP-Rab1b dynamics in HeLa cells. Time-lapse
microscopy indicated that the majority of the Rab1b-labeled punctuated structures are relatively short-lived with
limited-range movements. FRAP of Golgi GFP-Rab1bwt showed rapid recovery (t1/2 120 s) with minimal dependence on
microtubules. Our data support a model where Rab1b-GTP induces GBF1 recruitment at the ERES interface and at the
Golgi complex where it is required for COPII/COPI exchange or COPI vesicle formation, respectively.
microtubules. Our data support a model where Rab1b-GTP induces GBF1 recruitment at the ERES interface and at the
Golgi complex where it is required for COPII/COPI exchange or COPI vesicle formation, respectively.
1/2 120 s) with minimal dependence on
microtubules. Our data support a model where Rab1b-GTP induces GBF1 recruitment at the ERES interface and at the
Golgi complex where it is required for COPII/COPI exchange or COPI vesicle formation, respectively.