title: Interaction of FK506-binding protein 13 with brefeldin A-inhibited guanine nucleotide-exchange protein 1 (BIG1): effects of FK506.
abstract: BIG1 and BIG2 are brefeldin A-inhibited guanine nucleotide-exchange proteins that activate ADP-ribosylation factors (ARFs), critical components of vesicular trafficking pathways. These proteins can exist in macromolecular complexes and move between Golgi membranes and cytosol. In the BIG1 molecule, a centrally located Sec7 domain is responsible for ARF activation, but functions of other regions are largely unknown. Yeast two-hybrid screens of a human placenta cDNA library with BIG1 cDNA constructs revealed specific interaction of the N-terminal region (amino acids 1-331) with FK506-binding protein 13 (FKBP13). The association was confirmed by immunoprecipitation of both endogenous BIG1 and FKBP13 from Jurkat T cells with antibodies against either one. Binding of BIG1, BIG2, and ARF to cell membranes in vitro was increased by guanosine 5'-[gamma-thio]triphosphate, and further increases were induced by FK506. Incubation of Jurkat T cells with FK506 increased binding of BIG1, BIG2, and ARF to Golgi and other membranes in a time- and concentration-dependent manner, without effects on clathrin or gamma-adaptin binding. Binding of BIG1, BIG2, and ARF to membranes was also increased by L-732,531, an agonist structurally related to FK506, but was not increased by a related antagonist, L-685,818, nor by cyclosporin A or rapamycin. These findings are consistent with a role for FKBP13 and FK506 in vesicular trafficking, influencing ARF activity through their guanine nucleotide-exchange proteins.
authors.affiliation: Pulmonary-Critical Care Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 5N307, MSC 1434, Bethesda, MD 20892-1434, USA.
authors.forename: Philip Ian
authors.initials: PI
authors.lastname: Padilla
authors.forename: Min-Ju
authors.initials: MJ
authors.lastname: Chang
authors.forename: Gustavo
authors.initials: G
authors.lastname: Pacheco-Rodriguez
authors.forename: Ronald
authors.initials: R
authors.lastname: Adamik
authors.forename: Joel
authors.initials: J
authors.lastname: Moss
authors.forename: Martha
authors.initials: M
authors.lastname: Vaughan
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D015153:Blotting, Western; D020126:Brefeldin A / Q000494:pharmacology*; D002462:Cell Membrane / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism; D003001:Cloning, Molecular; D016572:Cyclosporine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D019169:Jurkat Cells; D011233:Precipitin Tests; D011485:Protein Binding; D020123:Sirolimus / Q000494:pharmacology; D013347:Subcellular Fractions / Q000378:metabolism; D016559:Tacrolimus / Q000031:analogs & derivatives* / Q000494:pharmacology; D022021:Tacrolimus Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors; D020798:Two-Hybrid System Techniques
chemical_list: C119087:ARFGEF1 protein, human; D002966:Clathrin; D004791:Enzyme Inhibitors; D020662:Guanine Nucleotide Exchange Factors; D007166:Immunosuppressive Agents; C070133:FKBP-13; D020126:Brefeldin A; D000244:Adenosine Diphosphate; C110188:32-O-(1-hydroxyethylindol-5-yl)ascomycin; D016572:Cyclosporine; D019204:GTP-Binding Proteins; D022021:Tacrolimus Binding Proteins; D020123:Sirolimus; D016559:Tacrolimus