High impact information on GEA2

• Mutations in a highly conserved region of the Arf1p activator GEA2 block anterograde Golgi transport but not COPI recruitment to membranes [1].
• This interaction involves a domain of Gea1p and Gea2p that is conserved in the eukaryotic orthologues of the Gea proteins [2].
• We demonstrate molecular interaction between the yeast Gmh1p and the large ARF-GEFs Gea1p and Gea2p [2].
• Conditional mutants defective in both GEA1 and GEA2 accumulate endoplasmic reticulum and Golgi membranes under restrictive conditions [3].
• The membrane-bound forms, at least one of which, Gea2p, can be visualized on Golgi structures, are both required for vesicle budding and protein transport from the Golgi to the endoplasmic reticulum [3].

Biological context of GEA2

• GEA1 and GEA2 have at least partially overlapping functions, because deletion of either gene results in no obvious phenotype, whereas the double null mutant is inviable [3].
• We have identified an important functional region of the yeast Arf1 activator Gea2p upstream of the catalytic Sec7 domain and characterized a set of temperature-sensitive (ts) mutants with amino acid substitutions in this region [1].
• Comparison with Gea2 in complex with nucleotide-free Arf1 Delta 17 [Goldberg, J. (1998) Cell 95, 237-248] reveals that Arf induces closure of the two subdomains that form the sides of its active site [4].

Anatomical context of GEA2

• A role for GEA1 and GEA2 in the organization of the actin cytoskeleton in Saccharomyces cerevisiae [5].
• In yeast, Gea2p has been implicated in trafficking through the Golgi apparatus and in maintaining Golgi structure [6].

Associations of GEA2 with chemical compounds

• The GEA1 and GEA2 genes, which code for paralog guanosine exchange factors for Arf proteins, were identified as multicopy suppressors of the mutant phenotype [5].
• COPI in these mutants is released from Golgi membranes by brefeldin A, a drug that binds directly to Gea2p and blocks Arf1 activation [1].

Physical interactions of GEA2

• Here we show that Drs2p interacts directly with Gea2p, both in vitro and in vivo [6].

Other interactions of GEA2

• The ADP ribosylation factor-nucleotide exchange factors Gea1p and Gea2p have overlapping, but not redundant functions in retrograde transport from the Golgi to the endoplasmic reticulum [3].
• Very close upstream from the URA3 gene, the 3'-end of a gene encoding a Gea2-like protein was identified [7].
• The Arf activator Gea2p and the P-type ATPase Drs2p interact at the Golgi in Saccharomyces cerevisiae [6].
• Here the contribution of the flexibility of Sec7 domains to the exchange reaction was investigated with the crystal structure of the unbound Sec7 domain of yeast Gea2 [4].

References