Abstract
The network of protein–protein interactions of the Dictyostelium discoideum autophagy pathway was investigated by yeast two-hybrid screening of the conserved autophagic proteins Atg1 and Atg8. These analyses confirmed expected interactions described in other organisms and also identified novel interactors that highlight the complexity of autophagy regulation. The Atg1 kinase complex, an essential regulator of autophagy, was investigated in detail here. The composition of the Atg1 complex in D. discoideum is more similar to mammalian cells than to Saccharomyces cerevisiae as, besides Atg13, it contains Atg101, a protein not conserved in this yeast. We found that Atg101 interacts with Atg13 and genetic disruption of these proteins in Dictyostelium leads to an early block in autophagy, although the severity of the developmental phenotype and the degree of autophagic block is higher in Atg13-deficient cells. We have also identified a protein containing zinc-finger B-box and FNIP motifs that interacts with Atg101. Disruption of this protein increases autophagic flux, suggesting that it functions as a negative regulator of Atg101. We also describe the interaction of Atg1 kinase with the pentose phosphate pathway enzyme transketolase (TKT). We found changes in the activity of endogenous TKT activity in strains lacking or overexpressing Atg1, suggesting the presence of an unsuspected regulatory pathway between autophagy and the pentose phosphate pathway in Dictyostelium that seems to be conserved in mammalian cells.
Highlights
Autophagy is an intracellular degradation pathway that occurs in all eukaryotic organisms analysed to date
We found that Atg101, FIP200, Atg13 and AreA are uniformly distributed in the cytoplasm
We have investigated the network of protein–protein interactions by yeast two-hybrid analysis of the conserved autophagic proteins Atg1 and Atg8 in D. discoideum
Summary
Autophagy is an intracellular degradation pathway that occurs in all eukaryotic organisms analysed to date. This process has been associated with numerous pathologies and dysfunctions such as cancer, neurodegenerative diseases, aging, heart and liver diseases, metabolic dysfunction and oxidative stress [1]. The simple biochemical compounds are transported back into the cytoplasm where they can be used for energy production or recycling This mechanism is tightly regulated by a number of complexes formed by the so-called autophagy-related proteins (Atg proteins). These complexes regulate the induction, elongation and maturation of the autophagosomes [2]. The first steps of induction and nucleation are controlled by the serine/threonine kinase Atg1/
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
