Cybr, a cytokine-inducible protein that binds cytohesin-1 and regulates its activity

J. Galon, J.J. O'Shea, M. Vaughan, P. Tang, T.P. Cheng, D. Agnello, C- Wu, B.D. Hissong, W.T. Watford, H- Ahn, J. Moss, Massimo Gadina

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36 Citations (Scopus)


Cytokines regulate lymphocyte development and differentiation, but precisely how they control these processes is still poorly understood. By using microarray technology to detect cytokine-induced genes, we identified a cDNA encoding Cybr, which was increased markedly in cells incubated with IL-2 and IL-12. The mRNA was most abundant in hematopoietic cells and tissues. The predicted amino acid sequence is similar to that of GRP-1-associated protein (GRASP), a recently identified retinoic acid-induced cytohesin-binding protein. Physical interaction, dependent on the coiled-coil domains of Cybr and cytohesin-1, was demonstrated by coimmunoprecipitation of the overexpressed proteins from 293T cells. Cytohesin-1, in addition to its role in cell adhesion, is a guanine nucleotide-exchange protein activator of ARF GTPases. Acceleration of guanosine 5'-O-(thiotriphosphate) binding to ARF by cytohesin-1 in vitro was enhanced by Cybr. Because the binding protein modified activation of ADP ribosylation factor by cytohesin-1, we designate this cytokine-inducible protein Cybr (cytohesin binder and regulator).
Original languageEnglish
Pages (from-to)2625-2629
Number of pages5
JournalProceedings of the National Academy of Sciences
Issue number5
Publication statusPublished - 05 Mar 2002

ASJC Scopus subject areas

  • Genetics
  • General


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