Dominant negative form of signal-regulatory protein-alpha (SIRPalpha /SHPS-1) inhibits tumor necrosis factor-mediated apoptosis by activation of NF-kappa B.
Genetic suppressor element (GSE) methodology was applied to identify new genes controlling cell response to tumor necrosis factor (TNF). A retroviral library of randomly fragmented normalized cDNA from mouse fibroblasts was screened for GSEs capable of protecting NIH3T3 cells from TNF-induced apoptosis. The most abundant among isolated GSEs represented a fragment of cDNA encoding the C-terminal cytoplasmic region of the immunoglobulin family inhibitory receptor, SHPS-1 (mouse homologue of human SIRPalpha). Ectopic expression of this fragment (both from human and mouse versions) increased the NF-kappaB-dependent transcription in three cell lines tested; this effect could be reduced by the expression of full-length SIRPalpha, suggesting that the isolated GSE acts through a dominant negative mechanism. GSE-mediated activation of NF-kappaB depended on the presence of serum, was abrogated by wortmannin, and was associated with phosphorylation of PKB/Akt, suggesting that Akt mediates it. These data indicate that SIRPalpha/SHPS-1 is involved in negative regulation of NF-kappaB signaling.
Neznanov
Nickolay
N
Department of Virology, Lerner Research Institute, Cleveland Clinic Foundation, Ohio 44195, USA. neznann@ccf.org
Neznanova
Lubov
L
Kondratov
Roman V
RV
Burdelya
Ludmila
L
Kandel
Eugene S
ES
O'Rourke
Donald M
DM
Ullrich
Axel
A
Gudkov
Andrei V
AV
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D000943:Antigens, Differentiation; D017209:Apoptosis / Q000502:physiology*; D001483:Base Sequence; D003593:Cytoplasm / Q000378:metabolism; D017931:DNA Primers; D006367:HeLa Cells; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D039842:Neural Cell Adhesion Molecule L1 / Q000737:chemistry / Q000502:physiology*; D011971:Receptors, Immunologic; D017386:Sequence Homology, Amino Acid; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
D000943:Antigens, Differentiation; D017931:DNA Primers; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D039842:Neural Cell Adhesion Molecule L1; C501922:Sirpa protein, mouse; D011971:Receptors, Immunologic; C501920:SIRPA protein, human; D014409:Tumor Necrosis Factor-alpha