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The role of G‐protein in matrix‐mediated motility of highly and poorly invasive melanoma cells
Author(s) -
Lester Bruce R.,
Weinstein Lee S.,
McCarthy James B.,
Sun Zhengqi,
Smith Ron S.,
Furcht Leo T.
Publication year - 1991
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910480121
Subject(s) - motility , biology , pertussis toxin , fibronectin , microbiology and biotechnology , laminin , extracellular matrix , messenger rna , protein biosynthesis , g protein , signal transduction , biochemistry , gene
Membranes from 2 K1735 murine melanoma clones of high invasive capacity show increased amounts of pertussis toxin (PT) substrate when compared to a weakly invasive cellular counterpart. Using a panel of specific G‐protein antibodies, we identified G iα2 as the PT‐sensitive G‐protein uniquely abundant in highly invasive cells. In addition, RNA hybridization results confirm the immunoblot observations that G iα2 is present at higher levels in strongly invasive cells. This result suggests that the elevated expression of G iα2 in highly invasive cells is not entirely due to differences in either translational efficiency or protein degradation but is related to altered RNA transcriptional initiation, processing and/or degradation. ADP‐ribosylation of G 1 α‐subunits by PT inhibited the fi‐bronectin, laminin and collagen type‐IV‐stimulated motility of the 2 highly invasive clones, while PT treatment of cells from a poorly invasive clone resulted in little or no reduction of the fibronectin, laminin or collagen type‐IV‐stimulated lower motility. Furthermore, PT treatment of highly or poorly invasive KI735 clones does not result in any alteration in cellular cAMP accumulation, suggesting that the PT substrate is not linked with the adenylyl cyclase enzyme complex. The data suggest that a PT‐sensitive G‐protein, probably G iα2 , regulates second messenger pathways that contribute to elevated motility in highly invasive KI735 cells.