Is the integrity of Gpm6a s Transmembrane Domains important in Filopodium Formation?

KARINA FORMOSO; ALBERTO C C FRASCH; CAMILA SCORTICATI

Capital Federal

Workshop; Workshop: Fronteras en Biociencias; 2012

Max plank y MINCyT

Neuronal glycoprotein M6a is involved in neuronal plasticity (e.g. neurite outgrowth, filopodium and synapses formation) through unknown mechanisms.M6a has four transmembrane domains (TMs) and shares structural similarity with the tetraspanin protein family. The function of several tetraspanins is mediated by their ability to self-associate and interact with different membrane proteins and lipids through specific alpha-helix residues.Our aim is to assess the association between genetic variants in Gpm6as TMs and filopodium induction in hippocampal cultured neurons. Three replacement polymorphisms, here named SNP1 (F93C) and SNP2 (I97S) in TM2 and SNP3 (W141R) in TM3, were found in the TMs coding regions of the Gpm6a gene.We used site-directed mutagenesis to construct a panel of mutants with the SNPs introduced into the M6a-EGFP-C1 plasmid. To study the ability of M6a to induce filopodium formation, the different mutants were overexpressed in primary culture of hippocampal neurons and in the cellular line N2a. Our results showed that overexpression of all SNPs significantly decreased filopodium density compared with control group. These results lead to the conclusion that M6a SNPs reduce neuronal plasticity.