title: DelGEF, a homologue of the Ran guanine nucleotide exchange factor RanGEF, binds to the exocyst component Sec5 and modulates secretion.
abstract: In order to identify the function of deafness locus putative guanine nucleotide exchange factor (DelGEF), a protein homologous to the nucleotide exchange factor for the small GTPase Ran, a cDNA library was screened for interacting proteins using a yeast two-hybrid system. The human homologue of Sec5, a protein involved in vesicle transport and secretion, was identified as a binding partner. The interaction between DelGEF and Sec5 was found to be dependent on Mg2+ and stimulated by guanosine triphosphate (GTP) or deoxycytidine triphosphate (dCTP). Downregulation of endogenous DelGEF in HeLa cells induced increased extracellular secretion of proteoglycans indicating a possible role for DelGEF in the secretion process.
authors.affiliation: Division for Molecular Biology of Mitosis, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.
authors.forename: Mikael
authors.initials: M
authors.lastname: Sjölinder
authors.forename: Jörg
authors.initials: J
authors.lastname: Uhlmann
authors.forename: Herwig
authors.initials: H
authors.lastname: Ponstingl
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D002412:Cations / Q000494:pharmacology; D015536:Down-Regulation; D005089:Exocytosis; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D008670:Metals / Q000494:pharmacology; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D011509:Proteoglycans / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D017385:Sequence Homology; D014018:Tissue Distribution; D020798:Two-Hybrid System Techniques; D033921:Vesicular Transport Proteins; D020931:ran GTP-Binding Protein / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D002412:Cations; C470182:EXOC2 protein, human; D020662:Guanine Nucleotide Exchange Factors; D008565:Membrane Proteins; D008670:Metals; D009711:Nucleotides; D016376:Oligonucleotides, Antisense; D011509:Proteoglycans; D012333:RNA, Messenger; C400705:SERGEF protein, human; D033921:Vesicular Transport Proteins; D020931:ran GTP-Binding Protein