About the lab

We are interested on understanding the molecular basis of Congenital Disorders of Glycosylation, using fission yeast mutants as a model organisms, and focusing on basic cell glycobiology underlying processes of the diseases. In particular, we focus in N-glycosylation and in the early steps of N-glycan processing.
We also use yeasts to express recombinant proteins, to perform functional complementation studies, to engineer strains to be used in bioremediation processes and other biotechnology applications.

Featured research (24)

The receptor binding domain (RBD) of the Spike protein from SARS-CoV-2 is a promising candidate to develop effective COVID-19 vaccines since it can induce potent neutralizing antibodies. We have previously reported the highly efficient production of RBD in Pichia pastoris , which is structurally similar to the same protein produced in mammalian HEK-293T cells. In this work we designed an RBD multimer with the purpose of increasing its immunogenicity. We produced multimeric particles by a transpeptidation reaction between RBD expressed in P. pastoris and Lumazine Synthase from Brucella abortus (BLS), which is a highly immunogenic and very stable decameric 170 kDa protein. Such particles were used to vaccinate mice with two doses 30 days apart. When the particles ratio of RBD to BLS units was high (6–7 RBD molecules per BLS decamer in average), the humoral immune response was significantly higher than that elicited by RBD alone or by RBD-BLS particles with a lower RBD to BLS ratio (1–2 RBD molecules per BLS decamer). Remarkably, multimeric particles with a high number of RBD copies elicited a high titer of neutralizing IgGs. These results indicate that multimeric particles composed of RBD covalent coupled to BLS possess an advantageous architecture for antigen presentation to the immune system, and therefore enhancing RBD immunogenicity. Thus, multimeric RBD-BLS particles are promising candidates for a protein-based vaccine .
We covalently coupled the RBD domain of SARS-CoV-2 produced in Pichia pastoris to a decameric carrier to produce a potent immunogen
Autophagy is an evolutionary conserved process by which eukaryotic cells undergo self-digestion of cytoplasmic components. Here we report that a novel Drosophila immunophilin, which we have named Zonda, is critically required for starvation-induced autophagy. We show that Zonda operates at early stages of the process, specifically for Vps34-mediated phosphatidylinositol 3-phosphate (PI3P) deposition. Zonda displays an even distribution under basal conditions, and soon after starvation nucleates in endoplasmic reticulum-associated foci that colocalize with omegasome markers. Zonda nucleation depends on Atg1, Atg13 and Atg17 but does not require Vps34, Vps15, Atg6 or Atg14. Zonda interacts physically with ATG1 through its kinase domain, as well as with ATG6 and Vps34. We propose that Zonda is an early component of the autophagy cascade necessary for Vps34-dependent PI3P deposition and omegasome formation.
UDP-Glc entrance into the endoplasmic reticulum (ER) of eukaryotic cells is a key step in the quality control of glycoprotein folding, a mechanism requiring transfer of a Glc residue from the nucleotide sugar to glycoprotein folding intermediates by the UDP-Glc:glycoprotein glucosyltransferase (UGGT). According to a bioinformatics search there are only eight genes in the Schizosaccharomyces pombe genome belonging to the three Pfam families to which all known nucleotide sugar transporters (NST) of the secretory pathway belong. The protein products of two of them (hut1(+) and yea4(+)) localize to the ER, those of genes gms1(+), vrg4(+), pet1(+), pet2(+) and pet3(+) to the Golgi, whereas that of gms2(+) has an unknown location. Here we demonstrate that: 1) Δhut1 and Δgpt1 (UGGT null) mutants share several phenotypic features; 2) Δhut1 mutants show a 50% reduction in UDP-Glc transport into ER-derived membranes; 3) in vivo UDP-Glc ER entrance occurred in Δhut1Δyea4Δgms2 mutants and in cells in which Δhut1 disruption was combined with that of each of four of the genes encoding Golgi-located proteins. We conclude that the hut1(+) gene product is involved in UDP-Glc entrance into the ER, but that at least another as yet unknown NST displaying an unconventional sequence operates in the yeast secretory pathway as disruption of all genes whose products localize to the ER or have an unknown location did not obliterate UDP-Glc ER entrance. This conclusion agrees with our previous results showing that UDP-Glc entrance into the yeast ER does not follow the classical NST antiport mechanism.

Lab head

Cecilia D'Alessio
Department
  • Department of Physiology, Molecular and Cellular Biology
About Cecilia D'Alessio
  • In the lab we are interested on understanding the molecular basis of Congenital Disorders of Glycosylation. We use fission yeast mutants as a model organism and focus on basic cell glycobiology underlying processes of the diseases. In particular, we focus in N-glycosylation and in the early steps of N-glycan processing. We also use different yeasts to express recombinant proteins, and we engineere yeast to use in bioremediation processes

Members (4)

Tommy Idrovo
  • Universidad de Buenos Aires
Giovanna Gallo
  • National University of Cuyo
Tomás Zubak
  • Argentine University of Business (UADE)