Receptor for activated C-kinase (RACK-1), a WD motif-containing protein, specifically associates with the human type I IFN receptor.
The cytoplasmic domain of the human type I IFN receptor chain 2 (IFNAR2c or IFN-alphaRbetaL) was used as bait in a yeast two-hybrid system to identify novel proteins interacting with this region of the receptor. We report here a specific interaction between the cytoplasmic domain of IFN-alphaRbetaL and a previously identified protein, RACK-1 (receptor for activated C kinase). Using GST fusion proteins encoding different regions of the cytoplasmic domain of IFN-alphaRbetaL, the minimum site for RACK-1 binding was mapped to aa 300-346. RACK-1 binding to IFN-alphaRbetaL did not require the first 91 aa of RACK-1, which includes two WD domains, WD1 and WD2. The interaction between RACK-1 and IFN-alphaRbetaL, but not the human IFN receptor chain 1 (IFNAR1 or IFN-alphaRalpha), was also detected in human Daudi cells by coimmunoprecipitation. RACK-1 was shown to be constitutively associated with IFN-alphaRbetaL, and this association was not effected by stimulation of Daudi cells with type I IFNs (IFN-beta1b). RACK-1 itself did not become tyrosine phosphorylated upon stimulation of Daudi cells with IFN-beta1b. However, stimulation of cells with either IFN-beta1b or PMA did result in an increase in detectable immunofluorescence and intracellular redistribution of RACK-1.
Croze
E
E
Department of Immunology, Berlex Biosciences, Richmond CA 94804, USA. ed_croze@berlex.com
Usacheva
A
A
Asarnow
D
D
Minshall
R D
RD
Perez
H D
HD
Colamonici
O
O
D020816:Amino Acid Motifs / Q000235:genetics / Q000276:immunology; D001224:Aspartic Acid; D002460:Cell Line; D004789:Enzyme Activation / Q000235:genetics / Q000276:immunology; D006801:Humans; D007370:Interferon Type I / Q000378:metabolism* / Q000494:pharmacology; D007424:Intracellular Fluid / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008565:Membrane Proteins; D010449:Peptide Mapping; D011233:Precipitin Tests; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D053633:Receptor, Interferon alpha-beta; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017471:Receptors, Interferon / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics / Q000276:immunology; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014364:Tryptophan; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques
C507964:IFNAR1 protein, human; D007370:Interferon Type I; D008565:Membrane Proteins; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface; D017471:Receptors, Interferon; D053633:Receptor, Interferon alpha-beta; D001224:Aspartic Acid; D014364:Tryptophan; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate