SNARE expression and distribution during 3T3-L1 adipocyte differentiation.
Differentiation of 3T3-L1 cells into adipocytes presupposes the expression of the glucose transporter isoform GLUT4 and the acquisition of insulin-dependent GLUT4 translocation from intracellular storage vesicles to plasma membrane. This ability to translocate GLUT4 depends on the presence of a set of proteins of the SNARE category that are essential in the fusion step. The expression and levels of some of these SNARE proteins are altered during 3T3-L1 differentiation. Levels of the v-SNARE protein cellubrevin and of the t-SNARE protein syntaxin 4 were increased in this process in parallel to GLUT4. However, the levels of SNAP-23, another t-SNARE, were maintained during differentiation. Immunofluorescence images of SNAP-23 showed the initial distribution of this protein in a perinuclear region before differentiation and its redistribution towards plasma membrane in the adipocyte form. These results suggest a capital role in the expression levels and cellular distribution, during 3T3-L1 differentiation, of SNARE proteins involved in the late steps of GLUT4 translocation.
Torrejón-Escribano
Benjamín
B
Departament de Biologia Cel.lular i Anatomia Patológica, Universitat de Barcelona, Campus de Bellvitge, C/Feixa Llarga s/n, E-08907, L'Hospitalet de Llobregat, Spain.
Gómez de Aranda
Inmaculada
I
Blasi
Juan
J
D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology*; D000818:Animals; D002451:Cell Compartmentation; D002454:Cell Differentiation; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000494:pharmacology*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins; D021381:Protein Transport; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; D051040:Vesicle-Associated Membrane Protein 3; D033921:Vesicular Transport Proteins
D051275:Glucose Transporter Type 4; D007328:Insulin; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; C495693:Slc2a4 protein, mouse; D051040:Vesicle-Associated Membrane Protein 3; D033921:Vesicular Transport Proteins