Human hAtg2A protein expressed in yeast is recruited to preautophagosomal structure but does not complement autophagy defects of atg2Δ strain.

Yeast Atg2, an autophagy-related protein, is highly conserved in other fungi and has two homologues in humans, one of which is hAtg2A encoded by the hATG2A/KIAA0404 gene. Region of homology between Atg2 and hAtg2A proteins comprises the C-terminal domain. We used yeast atg2D strain to express the GFP-KIAA0404 gene, its ...
fragment or fusions with yeast ATG2, and study their effects on autophagy. The GFP-hAtg2A protein localized to punctate structures, some of which colocalized with Ape1-RFP-marked preautophagosomal structure (PAS), but it did not restore autophagy in atg2Δ cells. N-terminal fragment of Atg2 and N-terminal fragment of hAtg2A were sufficient for PAS recruitment but were not sufficient to function in autophagy. Neither a fusion of the N-terminal fragment of hAtg2A with C-terminal domain of Atg2 nor a reciprocal fusion were functional in autophagy. hAtg2A, in contrast to yeast Atg2, did not show interaction with the yeast autophagy protein Atg9 but both Atg2 proteins showed interaction with Atg18, a phospholipid-binding protein, in two-hybrid system. Moreover, deletion of ATG18 abrogated PAS recruitment of hAtg2A. Our results show that human hAtg2A can not function in autophagy in yeast, however, it is recruited to the PAS, possibly due to the interaction with Atg18.
Mesh Terms:
Amino Acid Sequence, Aminopeptidases, Autophagy, Cytoplasm, Genetic Complementation Test, Green Fluorescent Proteins, Humans, Membrane Proteins, Molecular Sequence Data, Phagosomes, Protein Structure, Tertiary, Protein Transport, Recombinant Fusion Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid, Two-Hybrid System Techniques, Vacuoles
Acta Biochim. Pol.
Date: Sep. 03, 2011
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