Identification of Axonal transport properties of VMAT2-YFP fluorescent vesicles

CROMBERG L; OTERO MG; FALZONE T

Huerta Grande,

Congreso; XXVI Congreso de la Sociedad Argentina de Neurociencias (SAN); 2011

SAN

Parkinson’s disease (PD) is characterized by reductions in dopamine neurotransmitter release, abnormal protein accumulation known as Lewy Bodies, and selective degeneration of dopamine neurons. Dopamine (DA) neurotransmission rely on ATP-dependent internalization of DA by the Vesicular Monoamine Transporter 2 (VMAT2) prior to Ca-mediated release. VMAT2 reductions in mice induce PD phenotypes and neurodegeneration suggesting the relevance for the study of VMAT2 distribution along neurons. To identify the axonal transport properties of VMAT2 we have generated a fusion to the Yellow Fluorescent Protein (VMAT2-YFP). Initially, sucrose density flotation experiments in transfected N2a cells revealed that VMAT-YFP floats associated to vesicular membranes. Movies from transfected mouse primary hippocampal neurons under live imaging experiments were transformed to kymographs for analysis revealing a vesicular axonal transport for VMAT2-YFP with XX% of anterograde, XX% of retrograde and XX% of stationary particles. Average speeds for anterograde (XXum/sec) and retrograde (XXum/sec) vesicle displacements correspond to motor dependent movement. These results suggest that VMAT2 axonal transport is necessary for normal DA neurotransmission and implies a high relevance for the identification of the motor moving VMAT2. In addition, VMAT2 axonal transport defects might have a significant impact in the manifestation of PD phenotypes and in the progression of DA neurodegeneration.