Cavin 1 and cavin 2 roles on adipocyte cell function

Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina

Caveolae are a specialized type of lipid rafts found in numerous cell types. These structures have been implicated as playing a role in a variety of metabolic regulation processes and are typically characterized by their association with the caveolin and cavin protein families. Caveolae are particularly enriched in adipocytes and here we analyze the effects of cavin 1 and cavin 2 knockdown in adipocyte functioning. We obtained several multiclonal mouse 3T3-L1 cell lines with reduced expression of cavin 1 or cavin 2 by small interfering RNA approach using lentiviral vectors. We observed that cavin 1, but not cavin 2, depletion affects adipocyte differentiation and that both knockdown cells showed a reduced number of caveolae. We also verified that cavin 1 and cavin 2 expressions levels are dependent on each other and that both knockdowns caused a specific decrease in glucose transporter 4 (GLUT4) protein levels. Besides the lower protein levels of GLUT4, both knockdown cells also fail to translocate the transporter to the plasma membrane in response to insulin, although the insulin signaling pathway was not affected. As a consequence, knockdown cells show reduced insulin-stimulated glucose transport. Our results underscore the importance of cavin 1 and cavin 2 in glucose uptake and adipocyte metabolism.