Complexin is present in skeletal muscle and may participate in GLUT4-exocytosis

MAYORGA LUIS S.; PAVAROTTI MARTÍN A; KLIP AMIRA

Mendoza

Jornada; XXXIV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2016

Sociedad Biología de Cuyo

GLUT4 is the main glucose transport expressed in muscle and adipose tissues, being stored in the small GLUT4 storage vesicles (GSVs).Both insulin and muscle contraction increase the GSVs transport and fusion with plasma membrane (GLUT4-exocytosis), critical processesfor cellular glucose uptake. Intracellular membrane fusions are carried out by SNAREs proteins and several accessory proteins.The t-SNAREs, sintaxina-4 and SNAP23, and the v-SNARE Synaptobrevin/Vamp2are the main SNAREs taking part in GSV fusion. SNAREs are constitutively active,and they need a large set of regulatory proteins. In this regard, the calciumsensor synaptotagmin and complexin play a key role in calcium-regulatedexocytosis in neuroendocrinal cells and spermatozoa. It is well establishedthat GLUT4-exocytosis requires calcium and calcium sensors (ESYT1 and Doc2B),however, there are not evidence about the presences and participationof complexin during this process in muscle cells. Therefore, the aim of thiswork was to study the presences of complexin in muscle cells and muscle tissue.Using approaches like western-blot, immunouorescence and RT-PCR wewere able to show the presence of complexin in L6-muscle cells and skeletalmuscle tissue, being complexin II the most abundant isoform. These ndingsencourage us to study the participation of complexin in GLUT4-exocytosis