Homophilic interactions of alpha protocadherins

FERRERO, FLORENCIA V. AND CRAMER PAULA.

Potrero de los Funes, San Luis

Congreso; XLVII reunión de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2011

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Clustered protocadherins (Pcdh) are a group of neuronal surface glycoproteins that are expressed in specific regions of the central nervous system (CNS) of vertebrates (brain cortex, olfactory bulb, spinal chord, hippocampus), enriched at synapses. They belong to the Cadherin superfamily, involved in Ca2+ dependent cell adhesion, but their function remains unknown. They consist of over 50 genes arranged in three clusters (alpha, beta and gamma). Combinatorial expression of these variants could help to establish neuronal identity. Single neurons express Pcdh isoforms monoallelically and stochastically, with the exception of the "c2 type" isoform. We want to understand the nature of Pcdh interactions with other proteins and whether these trigger cell adhesion and/or signaling processes. Our model consists of a mouse neuronal cell line expressing one Pcdh isoform at a time, fused to a fluorescent protein or tag. We have described that they engage in homophilic interactions at the cell surface, and that these are calcium independent. Now we report that isoforms of the alpha cluster differ in the dynamics of formation of contacts and that the proteins undergo processing along their membrane transit. We have noted variations between isoforms in the amount of unprocessed protein while the contacts mature. We want to relate these data to the involvement of Pcdhs in cell signaling cascades