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

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

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.

Potent transforming activity of the small GTP-binding protein Rit in NIH 3T3 cells: evidence for a role of a p38γ-dependent signaling pathway

FEBS Letters ◽  
2001 ◽  
Vol 511 (1-3) ◽  
pp. 15-20 ◽  
Author(s):  
Kaoru Sakabe ◽  
Hidemi Teramoto ◽  
Muriel Zohar ◽  
Babak Behbahani ◽  
Hiroshi Miyazaki ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Binding Protein ◽  
3T3 Cells ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Transforming Activity ◽  
Nih 3T3 ◽  
Dependent Signaling Pathway ◽  
Nih 3T3 Cells

scholarly journals Role of pertussis toxin-sensitive guanosine triphosphate-binding proteins in the response of erythroblasts to erythropoietin

Blood ◽  
1991 ◽  
Vol 77 (3) ◽  
pp. 486-492 ◽  
Author(s):  
BA Miller ◽  
K Foster ◽  
JD Robishaw ◽  
CF Whitfield ◽  
L Bell ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Pertussis Toxin ◽  
Binding Proteins ◽  
Binding Protein ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Guanosine Triphosphate ◽  
Gtp Binding Protein ◽  
Gtp Binding

Abstract Human progenitor-derived erythroblasts have been recently shown to respond to erythropoietin (Epo) with an increase in intracellular free calcium concentration [Cac]. To explore the role of guanosine triphosphate (GTP)-binding proteins in mediating the rise in [Cac], single day 10 erythroid burst forming unit (BFU-E)-derived erythroblasts loaded with Fura-2 were pretreated with pertussis toxin (PT), stimulated with Epo, and [Cac] measured over 18 minutes with fluorescence microscopy coupled to digital video imaging. The [Cac] increase in day 10 erythroblasts stimulated with Epo was blocked by pretreatment with PT in a dose-dependent manner but not by heat- inactivated PT. These observations provided strong evidence that a PT- sensitive GTP-binding protein is involved. To further characterize the GTP-binding protein, day 10 erythroblast membrane preparations were solubilized, electrophoresed, and immunoblotted with antibodies specific for the known PT-sensitive G-protein subunits: the three subtypes of Gia (1,2, and 3) and Goa, Gia1 or Gia3 and Gia2 were identified but no Goa was found. To examine the influence of Epo on adenylate cyclase activity, day 10 erythroblasts were initially treated with Epo, isolated membrane preparations made, and cyclic adenosine monophosphate (cAMP) production by adenylate cyclase in membrane preparations in the presence of theophylline measured. Epo did not inhibit but significantly stimulated adenylate cyclase activity. However, the mechanism of increase of [Cac] appears to be independent of adenylate cyclase stimulation because treatment of erythroblasts with the cell-permeant dibutyryl cAMP failed to increase [Cac]. In summary, pertussis toxin blocks the increase in [Cac] in erythroblasts after Epo stimulation suggesting that this response is mediated through a pertussis toxin-sensitive GTP-binding protein. Candidate PT-sensitive GTP-binding proteins identified on day 10 erythroblasts were Gia 1, 2, or 3, but not Goa.

140 Analysis of the role of COP I protein and small GTP-binding protein in intracellular coated vesicle transport

1997 ◽  
Vol 15 (2) ◽  
pp. 126
Author(s):  
Y. Funasaka ◽  
K. Araki ◽  
A.K. Chakraborty ◽  
A. Ito ◽  
E. Nishioka ◽  
...  
Keyword(s):  
Binding Protein ◽  
Vesicle Transport ◽  
Coated Vesicle ◽  
Gtp Binding Protein ◽  
Gtp Binding
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