Antigenic variation in Giardia lamblia: role of VSPs transmembrane domain in sensing and signaling.

TENAGLIA ALBANO H; RIOS DIEGO N.; MARTIN MARIA JULIA; LUJAN, HUGO D.; GARGANTINI PABLO R.

Cordoba

Congreso; 52 th Annual Meeting Argentine Society for Biochemistry and Molecular Biology; LII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

SAIB

Giardia lamblia trophozoites undergoantigenic variation, where one member of the Variant-specific Surface Protein(VSP) family isexpressed on the surface of proliferating trophozoites andperiodically replaced by another. VSPs comprise an N-terminal variabledomainand a highly conserved C-terminal region that includes a hydrophobictransmembrane domain (TMD) and a short cytoplasmicCRGKA tail. Despite the highdegree of conservation, the VSP TMD has received relatively little attention,possibly due to the factthat TMDs have often been viewed as passive anchorsequences that span the lipid bilayer. Accumulating evidence has implicatedTMDsin helix-helix interactions leading to dimerization and signal transduction. Wehave carried out TOXCAT assays to assess theability of VSP TMDs toself-interact and found that mutations of highly conserved aminoacids withinthis sequence can alter VSPTMD interactions. Our results suggest thatdimerization of VSPs via their TMDs play a role in the mechanism of signaltransduction inantibody-triggered antigenic variation