LOCALIZATION OF PTP1B IN NEURONS AND ASSOCIATION WITH N-CADHERIN

F. FUENTES; C. O. ARREGUI

Pinamar, provincia de Buenos Aires, Argentina

Congreso; XX Annual Meeting of the Argentine Society for Neurochemistry (SAN); 2005

Sociedad Argentina de Investigación Bioquímica (SAIB), Panamerican Association for Biochemistry and (PABMB), Sociedad Argentina de Neuroquímica (SAN)

PTP1B is an endoplasmic reticulum (ER) phosphatase thatassociates with the intracellular domain of N-Cadherin. In neurons,N-cadherin is transported in dense-core vesicles to the axonalterminals. In this work we describe the localization of PTP1B inneurons, both in vitro and in situ. Furthermore, we examine whetherthe association of PTP1B with N-cadherin occurs during its transitalong the neuronal processes or after expression at the cell surface.To analyze the distribution of PTP1B in neurons in situ weelectroporated whole mounted chick retinas with GFP-PTP1B.Confocal analysis of retinal ganglion cells shows that GFP-PTP1Blocalizes in cell bodies, dendrites and axons. In cultured neuronsendogenous PTP1B shows a punctuate distribution among allneuronal domains, including growth cones and filopodia. At neuronalprocesses we see poor co-localization of PTP1B with cadherin, asrevealed by a pan-cadherin antibody. Similarly, we do not see colocalizationwith synatophysin, a marker of a different type oftransport vesicles. Inmunoclusterization of cell surface N-cadherininduces a selective co-clustering of PTP1B and beta catenin. Ourresults support the notion that PTP1B associates with cell surfaceN-cadherin.Supported by ANPCyT.