GDI1 encodes a GDP dissociation inhibitor that plays an essential role in the yeast secretory pathway

• Published in: The EMBO journal 1994-04, Vol.13 (7), p.1718-1728
• Main Authors: Garrett, M.D, Zahner, J.E, Cheney, C.M, Novick, P.J
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acid sequences; Base Sequence; beta-Fructofuranosidase; binding proteins; Biological and medical sciences; Biological Transport; Cloning, Molecular; Endoplasmic Reticulum - physiology; Endoplasmic Reticulum - ultrastructure; Fundamental and applied biological sciences. Psychology; Fungal Proteins - metabolism; gdi1 gene; Genes, Fungal - genetics; Genes. Genome; Glycoside Hydrolases - metabolism; Golgi Apparatus - physiology; Golgi Apparatus - ultrastructure; GTP-Binding Proteins - genetics; GTP-Binding Proteins - metabolism; Guanine Nucleotide Dissociation Inhibitors; guanosine diphosphate; guanosine triphosphate; interactions; Isoquinolines - metabolism; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; nucleotide sequences; protein secretion; protein transport; proteins; rab GTP-Binding Proteins; rho-Specific Guanine Nucleotide Dissociation Inhibitors; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae - ultrastructure; Saccharomyces cerevisiae Proteins; Sequence Analysis, DNA; Sequence Homology, Amino Acid; structural genes
• ISSN: 0261-4189; 1460-2075
• DOI: 10.1002/j.1460-2075.1994.tb06436.x

GTP binding proteins of the Sec4/Ypt/rab family regulate distinct vesicular traffic events in eukaryotic cells. We have cloned GDI1, an essential homolog of bovine rab GDI (GDP dissociation inhibitor) from the yeast Saccharomyces cerevisiae. Analogous to the bovine protein, purified Gdi1p slows the dissociation of GDP from Sec4p and releases the GDP-bound form from yeast membranes. Depletion of Gdi1p in vivo leads to loss of the soluble pool of Sec4p and inhibition of protein transport at multiple stages of the secretory pathway. Complementation analysis indicates that GDI1 is allelic to sec19-1. These results establish that Gdi1p plays an essential function in membrane traffic and are consistent with a role for Gdi1p in the recycling of proteins of the Sec4/Ypt/rab family from their target membranes back to their vesicular pools.