C. elegans UGGT-2 IS ESSENTIAL FOR VIABILITY ALTHOUGH IT LACKS GLUCOSYLTRANSFERASE ACTIVITY

BUZZI, LUCILA INÉS; SIMONETTA, SERGIO H.; PARODI, ARMANDO; CASTRO, OLGA A.

Mendoza

Congreso; SAIB (XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular); 2012

SAIB

The UDP-Glc:glycoprotein glucosyltransferase (UGGT) is the key component of the glycoprotein folding quality control mechanism in the endoplasmic reticulum. It behaves as a sensor of glycoprotein conformation as it exclusively glucosylates glycoproteins not displaying their native conformations. Most species have only one gene coding for UGGT-like proteins while species belonging to Euteleostomi and some species of nematodes belonging to genus Caenorhabditis have two homologues. In humans HUGT1 but not HUGT2 displayed UGGT activity. We report that uggt-2 is an essential gene although CeUGGT-2 lacks canonical UGGTactivity. We expressed CeUGGT-1 and CeUGGT-2 in S. pombe cells lacking UGGT activity and only CeUGGT-1 displayed UGGT activity. To evaluate if the CeUGGT-2 C-terminal domain were active in the context of SpUGGT we developed a chimeric protein between the SpUGGT N-terminal domain and CeUGGT-2 C-terminal catalytic domain. The chimera did not display UGGT activity, we therefore concluded that CeUGGT-2 C-terminal domain is also inactive. To evaluate if uggt-2 were an essential gene we analyzed the segregation of uggt-2(ok2510) allele in heterozygous uggt-2 worms (chromosome balanced with a GFP-marked translocation).More than 50% of the eggs were arrested and animals that matured to adulthood were all GFP positive, thus confirming that uggt-2 is an essential gene.