Elevation of carboxyl methylation activity on GTP-binding protein gamma-subunit in synovial tissues from rheumatoid arthritis: how does elevation of the methylation relate to the signal transduction system of rheumatoid arthritis?
We examined guanosine triphosphate (GTP)-binding proteins (G-proteins) in synovial tissues obtained from patients with rheumatoid arthritis or osteoarthritis. The results of immunoblot analysis with anti-bovine G-protein betagamma-subunit antibody in the rheumatoid synovial tissue were similar to those in the osteoarthritis synovial tissue. On the other hand, the carboxyl methylation activity on G-protein gamma-subunit in the rheumatoid synovial tissue was enhanced compared with that in the osteoarthritis synovial tissues: Km and Vm values were 2.6 microM and 10 pmol/mg x min, respectively, for the rheumatoid arthritis, and 4.8 microM and 5.6 pmol/mg x min, respectively, for the osteoarthritis. These results suggest that G-protein-linked signal transduction, in reference to carboxyl methylation of the gamma-subunit, is affected in rheumatoid tissues.
Hashimoto
H
H
Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, South-1, West-16, Chuo-ku, Sapporo 060-8556, Japan.
Sohma
H
H
Nagao
M
M
Ishii
S
S
Akino
T
T
D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D008745:Methylation; D010003:Osteoarthritis / Q000378:metabolism; D015398:Signal Transduction; D013583:Synovial Membrane / Q000378:metabolism*
D020962:Heterotrimeric GTP-Binding Proteins