The carboxy-terminus of yeast Atg13 binds phospholipid membrane via motifs that overlap with the Vac8-interacting domain.

The carboxy-terminus of yeast Atg13 binds phospholipid membrane via motifs that overlap with the Vac8-interacting domain.
Autophagy. 2019 Jul 27;:
Authors: Gatica D, Damasio A, Pascual C, Klionsky DJ, Ragusa MJ, Popelka H
Abstract
Macroautophagy/autophagy is a conserved catabolic recycling pathway involving the sequestration of cytoplasmic components within double-membrane vesicles termed autophagosomes. The autophagy-related (Atg) protein Atg13 is a key member of the autophagy initiation complex. The Atg13 C terminus is an intrinsically disordered region (IDR) harboring a binding site for the vacuolar membrane protein Vac8. Recent reports suggest Atg13 acts as a hub to assemble the initiation complex, and also participates in membrane recognition. Here we show that the Atg13 C terminus directly binds to lipid membranes via electrostatic interactions between positively charged residues in Atg13 and negatively charged phospholipids as well as a hydrophobic insertion of a Phe residue. We identified 2 sets of residues in the Atg13 IDR that affect its phospholipid-binding properties; these residues overlap with the Vac8-binding domain of Atg13. Our data indicate that Atg13 binding to phospholipids and Vac8 is mutually exclusive, and both are required for efficient autophagy.
PMID: 31352862 [PubMed - as supplied by publisher]

Source: Autophagy - July 26, 2019 Category: Cytology Authors: Gatica D, Damasio A, Pascual C, Klionsky DJ, Ragusa MJ, Popelka H Tags: Autophagy Source Type: research