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Updated: Sep 25, 2026

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay
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Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay

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ADP-ribosylation factor/COPI-dependent events at the endoplasmic reticulum-Golgi interface are regulated by the

Rafael García-Mata1, Tomasz Szul, Cecilia Alvarez

  • 1Department of Cell Biology, University of Alabama at Birmingham, 35924, USA.

Molecular Biology of the Cell
|June 17, 2003
PubMed

Insights

GBF1 regulates COPI-mediated transport at the ER-Golgi interface, controlling Golgi integrity and biogenesis. It facilitates the two-stage maturation of ER-to-Golgi intermediates, crucial for membrane traffic.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Membrane Trafficking

Background:

  • ADP-ribosylation factor (ARF) proteins and guanine nucleotide exchange factors (GEFs) are critical for intracellular transport.
  • The precise roles of specific ARF-GEFs in endoplasmic reticulum (ER)-to-Golgi transport remain incompletely understood.

Purpose of the Study:

  • To elucidate the function of GBF1, a Sec7-domain ARF-GEF, in regulating COPI-mediated transport at the ER-Golgi interface.
  • To investigate the mechanism by which GBF1 influences the formation and maturation of ER-to-Golgi transport intermediates.

Main Methods:

  • Investigated the role of GBF1 in COPI-mediated events using cell-based assays.
  • Analyzed the impact of GBF1 on the formation, differentiation, and translocation of pre-Golgi intermediates.
  • Examined the effect of brefeldin A on GBF1 recruitment and function.

Main Results:

  • GBF1 is essential for the formation, differentiation, and translocation of pre-Golgi intermediates and maintains Golgi integrity.
  • ER-to-Golgi intermediate formation occurs in two stages: a COPI-independent initial step and a GBF1-dependent COPI recruitment step for maturation.
  • Brefeldin A specifically inhibits GBF1 recruitment to these compartments.

Conclusions:

  • GBF1 plays a pivotal role in regulating COPI-mediated membrane traffic at the ER-Golgi interface.
  • Continuous GBF1 recruitment to specific membrane domains is vital for membrane remodeling, membrane traffic, and Golgi biogenesis.

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