PMID- 8858211
OWN - NLM
STAT- MEDLINE
DCOM- 19970224
LR  - 20190816
IS  - 0012-186X (Print)
IS  - 0012-186X (Linking)
VI  - 39
IP  - 8
DP  - 1996 Aug
TI  - GTPase activating protein activity for Rab4 is enriched in the plasma membrane of 
      3T3-L1 adipocytes. Possible involvement in the regulation of Rab4 subcellular 
      localization.
PG  - 899-906
AB  - The small guanosine 5'-triphosphate (GTP)ase Rab4 has been suggested to play a 
      role in insulin-induced GLUT4 translocation. Under insulin stimulation, GLUT4 
      translocates to the plasma membranes, while Rab4 leaves the GLUT4-containing 
      vesicles and becomes cytosolic. Rab proteins cycle between a GTP-bound active 
      form and a guanosine 5'-diphosphate (GDP)-bound inactive form. The intrinsic 
      GTPase activity of Rab proteins is low and the interconversion between the two 
      forms is dependent on accessory factors. In the present work, we searched for a 
      GTPase activating protein (GAP) for Rab4 in 3T3-L1 adipocytes. We used a 
      glutathione-S-transferase (GST)-Rab4 protein which possesses the properties of a 
      small GTPase (ability to bind GDP and GTP and to hydrolyse GTP) and can be 
      isolated in a rapid and efficient way. This GAP activity was observed in 3T3-L1 
      adipocyte lysates, and was able to accelerate the hydrolysis of the 
      [alpha-32P]GTP bound to GST-Rab4 into [alpha-32P]GDP. This activity, tentatively 
      called Rab4-GAP, was also present in 3T3-L1 fibroblasts. The Rab4-GAP activity 
      was present in total membrane fractions and nearly undetectable in cytosol. 
      Following subcellular fractionation, Rab4-GAP was found to be enriched in plasma 
      membranes when compared to internal microsomes. Insulin treatment of the cells 
      had no effect on the total Rab4-GAP activity or on its subcellular localization. 
      Taking our results together with the accepted model of Rab cycling in 
      intracellular traffic, we propose that Rab4-GAP activity plays a role in the 
      cycling between the GTP- and GDP-bound forms of Rab4, and thus possibly in the 
      traffic of GLUT4-containing vesicles.
FAU - Bortoluzzi, M N
AU  - Bortoluzzi MN
AD  - INSERM U 145, Faculte de Medecine, Nice, France.
FAU - Cormont, M
AU  - Cormont M
FAU - Gautier, N
AU  - Gautier N
FAU - Van Obberghen, E
AU  - Van Obberghen E
FAU - Le Marchand-Brustel, Y
AU  - Le Marchand-Brustel Y
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Germany
TA  - Diabetologia
JT  - Diabetologia
JID - 0006777
RN  - 0 (GTPase-Activating Proteins)
RN  - 0 (Glucose Transporter Type 4)
RN  - 0 (Insulin)
RN  - 0 (Membrane Proteins)
RN  - 0 (Monosaccharide Transport Proteins)
RN  - 0 (Muscle Proteins)
RN  - 0 (Phosphorus Radioisotopes)
RN  - 0 (Proteins)
RN  - 0 (Recombinant Fusion Proteins)
RN  - 0 (Slc2a4 protein, mouse)
RN  - 86-01-1 (Guanosine Triphosphate)
RN  - EC 2.5.1.18 (Glutathione Transferase)
RN  - EC 3.6.1.- (GTP Phosphohydrolases)
RN  - EC 3.6.1.- (GTP-Binding Proteins)
RN  - EC 3.6.5.2 (rab4 GTP-Binding Proteins)
SB  - IM
MH  - 3T3 Cells
MH  - Adipocytes/enzymology/*metabolism/ultrastructure
MH  - Animals
MH  - Cell Differentiation
MH  - Cell Membrane/enzymology/metabolism
MH  - Electrophoresis, Polyacrylamide Gel
MH  - GTP Phosphohydrolases/*metabolism
MH  - GTP-Binding Proteins/immunology/isolation & purification/*metabolism
MH  - GTPase-Activating Proteins
MH  - Glucose Transporter Type 4
MH  - Glutathione Transferase/metabolism
MH  - Guanosine Triphosphate/analysis/metabolism
MH  - Hydrolysis
MH  - Insulin/pharmacology
MH  - Membrane Proteins/metabolism
MH  - Mice
MH  - Monosaccharide Transport Proteins/metabolism
MH  - *Muscle Proteins
MH  - Phosphorus Radioisotopes
MH  - Proteins/*metabolism
MH  - Recombinant Fusion Proteins/immunology/isolation & purification/*metabolism
MH  - Subcellular Fractions/enzymology/metabolism
MH  - Time Factors
MH  - rab4 GTP-Binding Proteins
EDAT- 1996/08/01 00:00
MHDA- 1996/08/01 00:01
CRDT- 1996/08/01 00:00
PHST- 1996/08/01 00:00 [pubmed]
PHST- 1996/08/01 00:01 [medline]
PHST- 1996/08/01 00:00 [entrez]
AID - 10.1007/BF00403908 [doi]
PST - ppublish
SO  - Diabetologia. 1996 Aug;39(8):899-906. doi: 10.1007/BF00403908.