Analysis of Giardia lamblia protein-s-acyltransferases using complementation analysis in yeast

CORONEL C.; RÓPOLO AS.; VALDEZ TAUBAS J.

Córdoba

Congreso; - SAIB - 52th Annual Meeting Argentine society for biochemistry and molecular biology; 2016

Sociedad Argentina de Investigación en bioquímica y biología molecular

Protein S-acylation or palmitoylation, is a posttranslational modification that consist in the addition of long-chain lipids on cysteine residues through a thioesther bond. This modification regulates processes of great biological importance such us signal transduction and synaptic plasticity and it is also crucial for the infection of host cells by parasites. A family of enzymes named Palmitoyltransferases (PATs) is responsible for this modification. There are 7 members of this family in yeast and 23 in humans. Information regarding these enzymes is still scarce. PATs are very divergent even between orthologues from related organisms and this precludes the identification of orthologues based on sequence homology. Giardia lamblia has 9 putative PATs and substrates have been identified for only one. Yeast PATs are well characterized in terms of substrate specificity. We make use of the phenotypes produced by lack of individual yeast PATs to carry-out complementation analyses using G. lamblia putative PATs. Using this approach, we identified gla_6733 as a putative Akr1 orthologue and gla_8711 and gla_9529 as putative Swf1 orthologues, while gla_2116, gla_6733, gla_8619 y gla_16928 are able to fulfil the role of Pfa3 in agreement with Pfa3 substrates being more promiscuous. We are currently confirming these results by analyzing the palmitoylation of endogenous G. lamblia substrates in cells silenced for their respective PATs.