Cytohesin-1: structure, function, and ARF activation.
Mammalian cytohesins are a family of very similar guanine nucleotide-exchange proteins (GEPs) that activate ADP-ribosylation factors (ARFs). Cytohesins are multifunctional molecules comprising a Sec7 domain that is responsible for the GEP activity, a PH domain that binds specific phosphatidylinositol phosphates, and a coiled-coil domain responsible for homodimerization and interaction with other proteins. Cytohesin proteins are ubiquitous and have been implicated in several functions including cell spreading and adhesion, chemotaxis, protein trafficking, and cytoskeletal rearrangements, only some of which appear to depend on their ability to activate ARFs. Unlike the GEP activity of BIG1 and BIG2, the acceleration by cytohesins of guanine nucleotide exchange to generate active ARF-GTP is not inhibited by the fungal metabolite brefeldin, A (BFA). This chapter is concerned for the most part with cytohesin-1 and the assay of its GEP activity.
Pacheco-Rodriguez
Gustavo
G
Pulmonary-Critical Care Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
Moss
Joel
J
Vaughan
Martha
M
D000818:Animals; D019556:COS Cells; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D002522:Chlorocebus aethiops; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D017434:Protein Structure, Tertiary
D015815:Cell Adhesion Molecules; D020662:Guanine Nucleotide Exchange Factors; C100723:cytohesin-1