INVESTIGADORES
SCORTICATI Camila
congresos y reuniones científicas
Título:
Is the integrity of Gpm6as Transmembrane Domains important in Filopodium Formation? Formoso, K; Frasch, ACC and Scorticati, C
Autor/es:
FORMOSO, K; FRASCH, AC; SCORTICATI, C
Lugar:
Vancouver
Reunión:
Congreso; 6th Annual Canadian Neuroscience Meeting; 2012
Institución organizadora:
CNS
Resumen:
Neuronal glycoprotein M6a is
involved in hippocampal plasticity through still unknown mechanisms. Though it is not classified within Tetraspanin
protein family, M6a is commonly related to this family because of their similar
structure . It is well known that the ability to self-associate and interact
with different membrane proteins and lipids through specific alpha-helix
residues is what allows tetraspanins to carry out their functions. Previous
results have determined the existence of M6a-oligomers in neuronal membranes and
an in vitro assay demonstrated the
self-association of M6a-transmembrane domains (TM). The TMs of membrane proteins are a frequent target of disease causing
mutations that impair such interactions. In this sense, our aim is to
assess the association between genetic variants in Gpm6as. TMs and filopodium induction in neurons. Three nonsynonymous polymorphisms were found in the TMs coding regions of
the GPM6A gene (SNP1 (F93C) and SNP2 (197S) for TM2 and SNP3 (W141R) for
TM3). To study the ability of M6a to induce filopodium formation, the
different mutants were overexpressed in primary hippocampal neurons and in
neuroblastoma cell line, N2a. In neurons
overexpressing all mutants display reduced filopodia density. On the contrary,
in N2a cells only M6a-SNP3 mutant failed to induce filopodia formation. Moreover,
in non-permeabilized neurons only M6a-SNP3
clone was not recognized by monoclonal antibody directed to a major
extracellular loop of M6a and prevented the cell surface expression of M6a
which was retained in the endoplasmic reticulum showing a colocalization
pattern with calnexin. Altogether, in this work we provided evidence that all
SNPs impaired M6a plasticity in neurons. In the case of SNP3 this could be due
to the fact that M6a-TM3 mutation impaired the proper assembly required for
surface expression. In the case of SNP1 and SNP2 further studies are needed to
analyze a possible link between TM2-M6a mutants and reduced hippocampal
plasticity.