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Evaluation of the interaction between the kidney-type (KGA) glutaminase with the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-gamma)

Author(s):
Carolina Aparecida de Guzzi Cassago
Total Authors: 1
Document type: Doctoral Thesis
Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
Defense date:
Examining board members:
Ana Carolina Migliorini Figueira; Marília Meira Dias; Juliana Fattori; Marcio Chaim Bajgelman
Advisor: Sandra Martha Gomes Dias
Abstract

Cellular processes are largely mediated by the interaction between proteins. Moreover, the same protein interactions with different partners may lead to distinct cell responses in nature, often involving processes not previously scheduled for the same. The glutaminases isoenzymes are responsible for the glutamine conversion into glutamate replenishing the tricarboxylic acid cycle (TCA) and supporting its operation and generation of metabolites essential for the synthesis of macromolecules having particular importance for various tumor types. The GLS gene codes for isoforms kidney-type glutaminase (KGA) and glutaminase C (GAC). Although they share the same catalytic domain KGA isoform has other distinct domains containing sequences consensus LXXLL type (L = leucine and X = any amino acid), also called Nuclear Receptor boxes (NR box) typically present in coregulators of transcription factors of the type nuclear receptors. Yeast two hibrid assays revealed the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR) as a potential interaction partner of KGA. In this work, also by yeast two hybrid, it was defined that the interaction occurs between the N-terminal domain KGA that containing the NR box 1 (10LXXLL14) and domains of the DNA binding and ligand binding (DBD/LBD) of PPAR. Our data showed that the increased presence of PPAR in the cytoplasm is associated to a less proliferative state of prostate cancer cell lines, which was also obtained by overexpression of KGA. Moreover, in immunofluorescence studies of breast and prostate cancer cells, showed that KGA and PPAR were localized in the mitochondria, which results was confirmed by cell fractionation followed by immunoblotting. Finally, studies with q-PCR array showed that the increased expression KGA led to upregulation 4 gene expression and downregulation expression 1 target gene of PPAR. These genes are directly involved in the use of alternative energy sources or decreased oxidative stress. Accordingly, partnership between KGA and PPAR may be linked to best survival capacity of tumor cells in nutrient deprivation conditions. (AU)

FAPESP's process: 11/10127-2 - Studies of the nuclear location and nuclear receptor interaction of glutaminases
Grantee:Carolina Aparecida de Guzzi Cassago
Support type: Scholarships in Brazil - Doctorate