scholarly journals The GTP-binding protein of rod outer segments. I. Role of each subunit in the GTP hydrolytic cycle.

1987 ◽  
Vol 262 (19) ◽  
pp. 9316-9323 ◽  
Author(s):  
A Yamazaki ◽  
M Tatsumi ◽  
D C Torney ◽  
M W Bitensky
Keyword(s):  
Binding Protein ◽  
Rod Outer Segments ◽  
Gtp Binding Protein ◽  
Outer Segments ◽  
Gtp Binding

Photoreceptor rod outer segment 48-kDa protein has ATPase activity

1990 ◽  
Vol 5 (6) ◽  
pp. 585-589 ◽  
Author(s):  
Ari Sitaramayya ◽  
Shereen Hakki
Keyword(s):  
Atpase Activity ◽  
Cyclic Gmp ◽  
Slow Rate ◽  
Binding Protein ◽  
Rod Outer Segments ◽  
Light Activation ◽  
Visual Transduction ◽  
Gtp Binding Protein ◽  
Gtp Binding

AbstractThe role of 48-kDa protein in Visual transduction remains unresolved. Two hypotheses for its role in quenching the light activation of cyclic GMP cascade suggest that the protein binds to either phosphodiesterase or phosphorylated rhodopsin. Since the protein is also reported to bind ATP, we anticipated that the protein may have ATP hydrolyzing activity, and in analogy with the GTP-binding protein of the rod outer segments, such activity may be greatly enhanced by the elements of transduction cyclic GMP cascade, permitting the protein to function cyclically as GTP-binding protein does. We found that purified 48-kDa protein hydrolyzes ATP but at a slow rate of 0.04–0.05 per min. The Km for ATP is about 45–65 μM. The activity is inhibited noncompetitively by ADP with a Ki of about 50 μM. The ATPase activity of 48-kDa protein is not affected by rhodopsin, bleached rhodopsin, phosphorylated rhodopsin, unactivated cyclic GMP phosphodiesterase, or phosphodiesterase (PDE) activated by GMP PNP-bound G-protein. These data show that although 48-kDa protein has ATPase activity, lack of regulation of this activity by the elements of visual transduction makes it unlikely for this activity to have a role in quenching the light activation of cyclic GMP cascade.

134 Analysis of the role of small GTP binding protein Rab in intracellular melanosome transport

1996 ◽  
Vol 12 (2) ◽  
pp. 204
Author(s):  
K. Araki ◽  
T. Horikawa ◽  
K. Nakagawa ◽  
Y. Funasaka ◽  
M. Ichihashi
Keyword(s):  
Binding Protein ◽  
Gtp Binding Protein ◽  
Gtp Binding

A chimeric toxin to study the role of the 21 kDa GTP binding protein rho in the control of actin microfilament assembly.

1993 ◽  
Vol 12 (3) ◽  
pp. 921-931 ◽  
Author(s):  
P. Aullo ◽  
M. Giry ◽  
S. Olsnes ◽  
M.R. Popoff ◽  
C. Kocks ◽  
...  
Keyword(s):  
Binding Protein ◽  
Gtp Binding Protein ◽  
Actin Microfilament ◽  
Gtp Binding
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