41st FEBS Congress, Molecular and Systems Biology for a Better Life, Aydın, Türkiye, 3 - 08 Ağustos 2016, cilt.283, ss.1-441
Cardiolipin (CL) is a phospholipid which is localized exclusively
to the mitochondrial inner membrane (MIM). CL interacts with
proteins involved in oxidative phosphorylation and also plays a
role in the modulation of apoptosis and autophagy. We studied
the role of CL on autophagy/mitophagy, in two mutant strains
of S. cerevisiae, the Crd1Δ (cardiolipin synthase gene deleted)
strain and the Taz1Δ (Tafazzin, a critical cardiolipin modifying
enzyme gene deleted) strain and the wild-type S. cerevisiae strain
GA74-1A. Autophagy induction was monitored by GFP expression using Western blot and flow cytometric analyses. We observed that autophagy induction increased in three strains
which were grown in different media. Mitochondrial respiration,
mitochondrial membrane potential and the organization of mitochondrial protein complexes were also studied. In the wild-type
strain, while autophagy did not affect NADH-dependent mitochondrial respiration significantly, it positively affects succinatedependent respiration. In contrast, in the Taz1Δ strain, autophagy negatively affects succinate-dependent respiration. We
found that levels of complex IV subunit Cox2p changed in the in
Crd1Δ strain upon starvation. Measurement of mitochondrial
membrane potential (MMP) showed a decrease in Crd1Δ strain
grown in fermentative and non-fermentative media. Prolonged
autophagy induction diminished the level of MMP in all strains.
In addition, mRNA levels of Atg32 and Atg17 that are essential
proteins for mitophagy showed different profile in wild-type and
mutant yeast strains. We further analysed changes in lipid composition of mitochondria upon autophagy induction. The data
presented in this study on the possible roles of cardiolipin in
autophagy and mitophagy will contribute to the understanding
of the basic mechanisms of aging and neurodegenerative disorders.
Acknowledgement: This work was supported by The Scientific
And Technological Research Council Of Turkey (Grant number:
212T027).