scholarly journals Regulation of SNAREs by tomosyn and ROCK

2004 ◽  
Vol 166 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Toshiaki Sakisaka ◽  
Takeshi Baba ◽  
Shintaro Tanaka ◽  
Genkichi Izumi ◽  
Masato Yasumi ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
G Protein ◽  
Growth Cones ◽  
Snare Complex ◽  
Stable Complex ◽  
Small G Protein ◽  
Leading Edges

Extension of neurites requires the SNARE-dependent fusion of plasmalemmal precursor vesicles with the plasma membrane of growth cones. Here, we show that tomosyn localizes at the palm of growth cones and inhibits the fusion of the vesicles there, thus promoting transport of the vesicles to the plasma membrane of the leading edges of growth cones. Tomosyn localizes because ROCK activated by Rho small G protein phosphorylates syntaxin-1, which increases the affinity of syntaxin-1 for tomosyn and forms a stable complex with tomosyn, resulting in inhibition of the formation of the SNARE complex. In retraction of neurites, tomosyn localizes all over the edges of the neurites and inhibits fusion of the vesicles with the plasma membrane. Thus, tomosyn demarcates the plasma membrane by binding to syntaxin-1 phosphorylated by ROCK, and thereby regulates extension and retraction of neurites.

scholarly journals Single molecule imaging of activated small G protein Rac on the plasma membrane

2003 ◽  
Vol 43 (supplement) ◽  
pp. S101
Author(s):  
R. Nagai ◽  
T. Kobayashi ◽  
M. Murakami ◽  
T. Kawasaki ◽  
Y. Takeda ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
G Protein ◽  
Single Molecule ◽  
Single Molecule Imaging ◽  
Small G Protein

scholarly journals ADP-Ribosylation Factor 6 Delineates Separate Pathways Used by Endothelin 1 and Insulin for Stimulating Glucose Uptake in 3T3-L1 Adipocytes

2001 ◽  
Vol 21 (15) ◽  
pp. 5276-5285 ◽  
Author(s):  
J. Todd R. Lawrence ◽  
Morris J. Birnbaum
Keyword(s):  
Plasma Membrane ◽  
G Protein ◽  
Glucose Transport ◽  
Heterotrimeric G Protein ◽  
Endothelin 1 ◽  
Adp Ribosylation ◽  
Small G Protein ◽  
Hexose Uptake ◽  
Adp Ribosylation Factor ◽  
Glucose Carrier

ABSTRACT In 3T3-L1 adipocytes, both insulin and endothelin 1 stimulate glucose transport via translocation of the GLUT4 glucose carrier from an intracellular compartment to the cell surface. Yet it remains uncertain as to whether both hormones utilize identical pathways and to what extent each depends on the heterotrimeric G protein Gαq as an intermediary signaling molecule. In this study, we used a novel inducible system to rapidly and synchronously activate expression of a dominant inhibitory form of ADP-ribosylation factor 6, ARF6(T27N), in 3T3-L1 adipocytes and assessed its effects on insulin- and endothelin-stimulated hexose uptake. Expression of ARF6(T27N) in 3T3-L1 adipocytes was without effect on the ability of insulin to stimulate either 2-deoxyglucose uptake or the translocation of GLUT4 or GLUT1 to the plasma membrane. However, the same ARF6 inhibitory mutant blocked the stimulation of hexose uptake and GLUT4 translocation in response to either endothelin 1 or an activated form of Gαq, Gαq(Q209L). These results suggest that endothelin stimulates glucose transport through a pathway that is distinct from that utilized by insulin but is likely to depend on both a heterotrimeric G protein from the Gq family and the small G protein ARF6. These data are consistent with the interpretation that endothelin and insulin stimulate functionally different pools of glucose transporters to be redistributed to the plasma membrane.

scholarly journals Role of G protein beta gamma subunits in the regulation of the plasma membrane Ca2+ pump.

1992 ◽  
Vol 267 (4) ◽  
pp. 2375-2379 ◽  
Author(s):  
S Lotersztajn ◽  
C Pavoine ◽  
P Deterre ◽  
J Capeau ◽  
A Mallat ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
G Protein ◽  
Gamma Subunits

scholarly journals The actin cytoskeleton and small G protein RhoA are not involved in flow-dependent activation of ENaC

2010 ◽  
Vol 3 (1) ◽  
Author(s):  
Alexey V Karpushev ◽  
Daria V Ilatovskaya ◽  
Alexander Staruschenko
Keyword(s):  
Actin Cytoskeleton ◽  
G Protein ◽  
Small G Protein
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