INSULIN AND a2M* INDUCES THE EXOCYTIC TRAFFIC OF LRP1 FROM GSV?LIKE STRUCTURAL VESICLES

ACTIS DATO, VIRGINA; VAZQUEZ, MAXIMILIANO; CHIABRANDO, GUSTAVO

Cordoba, capital

Congreso; LII Reunion Anual de la Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular; 2016

Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular

LDL receptor-related protein 1 (LRP1) is an endicytic and signaling receptor present in dierent tissues and cell types. This receptoris intracellularly stored in non well-characterized structural vesicles from which can be sorted to plasma membrane(PM) in the presence of the alpha2-Macroglobulin (a LRP1-related ligand) or insulin (a LRP1-nonrelated ligand) through aputative exocytic route. We hypothesize that LRP1 is stored in GSV-like structural vesicles in all types of cells. Herein, we characterizethe structural vesicles storing LRP1 in a Muller Glial cell line, MIO-M1. By biotin-labeling protein assay we demonstratedthat LRP1 translocate to PM after insulin and 2M* stimulation , which was inhibited by the expression of a negativemutant of Rab10 GTPase. By confocal microscopy we found the LRP1 colocalization with GLUT4-GFP and sortilin, a markerof GSV. Finally, we demonstrate that HAmLRP4-GFP was tracked to PM in insulin and 2M*-stimulated cells. Thus, we concludethat LRP1 is stored in structural vesicles with GSV properties in MIO-M1 cells, from which is tracked to PM through anexocytic pathway