IHEM   20887
INSTITUTO DE HISTOLOGIA Y EMBRIOLOGIA DE MENDOZA DR. MARIO H. BURGOS
Unidad Ejecutora - UE
artículos
Título:
Insulin-induced exocytosis regulates the cell surface level of low density lipoprotein-related protein-1 in Müller Glial cells
Autor/es:
FADER, CLAUDIO M; ACTIS DATO, VIRGINIA; SÁNCHEZ, MARÍA C; CHIABRANDO, GUSTAVO A; GROSSO, RUBÉN A
Revista:
BIOCHEMICAL JOURNAL
Editorial:
PORTLAND PRESS LTD
Referencias:
Año: 2018 p. 1669 - 1685
ISSN:
0264-6021
Resumen:
Low-density lipoprotein (LDL) receptor-related protein-1 (LRP1) is expressed in retinal Müller glial cells (MGCs) and regulates intracellular translocation to the plasma membrane (PM) of the membrane proteins involved in cellular motility and activity. Different functions of MGCs may be influenced by insulin, including the removal of extracellular glutamate in the retina. In the present work, we investigated whether insulin promotes LRP1 translocation to the PM in the Müller glial-derived cell line MIO-M1. We demonstrated that LRP1 is stored in small vesicles containing an approximate size of 100 nm (mean diameter range of 100 nm to 120 nm), which were positive for sortilin and VAMP2, and also incorporated GLUT4 when it was transiently transfected.. Next, we observed that LRP1 translocation to the PM was promoted by insulin-regulated exocytosis through intracellular activation of the IR/PI3K/Akt axis and Rab-GTPase proteins such as Rab8A and Rab10. In addition, these Rab-GTPases regulated both the constitutive and insulin-induced LRP1 translocation to the PM. Finally, we found that dominant-negative Rab8A and Rab10 mutants impaired insulin-induced intracellular signalling of the IR/PI3K/Akt axis, suggesting that these GTPase proteins as well as the LRP1 level at the cell surface are involved in insulin-induced IR activation.