Golgi Brefeldin A Resistant Guanine Nucleotide Exchange Factor 1 (GBF1)

Members of the Sec7 domain family share a conserved region that forms a catalytic fold with guanine nucleotide exchange activity. In vitro, the Sec7 domain of several proteins catalyzes the activation of ADP-ribosylation factors (ARFs), suggesting that members of the Sec7 domain family represent specific guanine nucleotide exchange factors for the ARF GTPase family. Using 5-prime RACE, Mansour et al. (1998) isolated a cDNA corresponding to the remainder of the coding sequence. They designated the gene GBF1 (Golgi-specific brefeldin A resistance factor-1). The predicted 1,859-amino acid protein has a pI of 5.55 and contains a Sec7 domain and a proline-rich C terminus. A 7-kb GBF1 mRNA was expressed in all tissues tested by Northern blot analysis.