MOLECULAR AND MORPHOLOGICAL CHANGES IN TRANSPORT PLAYERS AFTER A SECRETORY STIMULATION

IRIS A. GARCÍA; HERNÁN MARTINEZ; CECILIA ALVAREZ

POTRERO DE LOS FUNES, SAN LUIS

Congreso; 47TH ANNUAL MEETING - ARGENTINA SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY RESERCH; 2011

SOCIEDAD ARGENTINA DE INVESTIGACIÓN EN BIOQUÍMICA Y BIOLOGÍA MOLECULAR

The exocytic and endocytic pathways are ubiquitous and essential for the export and import of proteins. Secretory tissues required extensive membrane transport activity to accomplish their secretory function; however, how a secretory stimulus regulates molecular and morphological changes in transport players is unclear. Here, a thyroid rat cell line (FRTL5) was used in order to study molecular and morphological changes of transport machinery after stimulation with thyroid stimulating hormone (TSH). TSH regulates thyroid growth and differentiation, and is required for the expression of thyroglobulin, thyroperoxidase and the Na/I symporter (NIS), necessary for the synthesis of thyroid hormones. Our results showed an increase of multiple transport proteins (Rab1b, GM130, Sec23a, Rab5a, Calreticulin and others) upon TSH addition. In agreement, an increase in their RNA levels was detected by Real Time PCR. Furthermore, morphological changes (analyzed by confocal microscopy) in the Golgi complex and COPII structures suggest that TSH induces their reorganization to deal with cargo increase. FRTL5 cells provide a good model to study organelle biogenesis/reorganization in the secretory pathway and will allow us to define molecular mechanisms that regulate changes in transport machinery after a secretory stimulus.