title: The molecular mechanism of Atg13 function in autophagy induction: What is hidden behind the data?
abstract: Atg13 is an essential subunit of the Atg1 autophagy initiation complex in yeast and its mammalian counterpart, ATG13, is indispensable for autophagy induction by the ULK1 complex. The N terminus of the protein folds into a HORMA domain, an architecture that has been revealed by crystallography.1-4In human cells, the ATG13 HORMA domain interacts directly with ATG14, a subunit of the class III phosphatidylinositol 3-kinase complex.5In budding yeast, the HORMA domain of Atg13 recruits Atg14, but a direct interaction remains to be proven.1The amino acid sequence that follows the HORMA domain does not adopt any 3-dimensional structure on its own; therefore, it is termed an intrinsically disordered region (IDR). Here we discuss the results of 2 recent studies in light of previous reports on Atg13 from yeast. Together, they yield an insight into the molecular mechanism for the function of this intriguing protein, and reveal why Atg13, as well as the mammalian homolog ATG13, cannot have a structurally rigid architecture.
authors.affiliation: a Life Sciences Institute, University of Michigan , Ann Arbor , MI , USA.
authors.forename: Hana
authors.initials: H
authors.lastname: Popelka
authors.affiliation: a Life Sciences Institute, University of Michigan , Ann Arbor , MI , USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Klionsky
mesh_terms: D001343:Autophagy; D000071183:Autophagy-Related Proteins / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
chemical_list: D000071183:Autophagy-Related Proteins; D029701:Saccharomyces cerevisiae Proteins
keywords: Atg13; autophagy; intrinsic disorder; structure; vacuole