Vanhove B, Hofer-Warbinek R, Kapetanopoulos A, Hofer E, Bach FH, de Martin R. Gem, a GTP-binding protein from mitogen-stimulated T cells, is induced in endothelial cells upon activation by inflammatory cytokines.
ENDOTHELIUM : JOURNAL OF ENDOTHELIAL CELL RESEARCH 1997;
5:51-61. [PMID:
9142321 DOI:
10.3109/10623329709044158]
[Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Using differential screening of cytokine-activated versus resting porcine aortic endothelial cells (PAEC), we have isolated a member of the family of Ras/GTP-binding proteins. The cDNA encodes a 34-kilodalton protein showing 97% homology to Gem, a gene recently isolated from activated T cells, likely representing its porcine homologue. The amino acid sequence differs from the Ras consensus by the absence of a C-terminal isoprenylation site and a glycine to glutamic acid substitution in the third GTP-binding domain. We report here, that pigGem mRNA is strongly inducible in PAEC upon activation by either IL-1 alpha, TNF alpha or lipopolysaccharide (LPS). Low constitutive expression is found in several organs. Epitope-tagged pigGem transfected into endothelial cells (EC) localizes to the cytoplasm and to the inner side of the plasma membrane. Structural features of Gem and its inducibility apparently restricted to T cells and endothelial cells, together with Rad, a GTPase overexpressed in skeletal muscle cells of type II diabetic individuals, define a new branch within the superfamily of GTP-binding proteins.
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