title: DNA damage signaling triggers the cytoplasm-to-vacuole pathway of autophagy to regulate cell cycle progression.
abstract: Budding yeast cells suffering a single unrepaired DNA double-strand break (DSB) trigger the ATR (Mec1)-dependent DNA damage checkpoint and arrest prior to anaphase for 12-15 h, following which they adapt and resume cell division. When the DNA lesion can be repaired, the checkpoint is extinguished and cells "recover" and resume mitosis. In this autophagic punctum, we report that hyperactivation of autophagy-specifically via the cytoplasm-to-vacuole targeting (Cvt) pathway-prevents both adaptation to, and recovery from, DNA damage, resulting in the permanent arrest of cells in G 2/M. We show that Saccharomyces cerevisiae deleted for genes encoding the Golgi-associated retrograde protein transport (GARP) complex are both adaptation- and recovery-defective. GARP mutants such as vps51Δ exhibit mislocalization of the key mitotic regulator, securin (Pds1), and its degradation by the vacuolar protease Prb1. In addition, separase (Esp1), is excluded from the nucleus, accounting for pre-anaphase arrest. Pds1 is degraded via the Cvt pathway. Many of the same defects seen by deleting GARP genes can be mimicked by hyperactivation of the Cvt pathway by overexpressing an unphosphorylatable form of ATG13 or by adding the TORC1 inhibitor rapamycin. These results suggest that nuclear events such as DNA damage can have profound effects on cytoplasmic processes and further expand the burgeoning connections between DNA damage and autophagy.
authors: Department of Biology and Rosenstiel Center, Brandeis University, Waltham, MA, USA.
authors: Vinay V
authors: VV
authors: Eapen
authors: James E
authors: JE
authors: Haber
mesh_terms: D001343:Autophagy; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism*; D004249:DNA Damage; D010450:Endopeptidases / Q000378:metabolism; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence / Q000379:methods; D008938:Mitosis; D009687:Nuclear Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D064249:Securin; D064247:Separase; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology; D014617:Vacuoles / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C578004:PDS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D049452:Green Fluorescent Proteins; D010450:Endopeptidases; C577986:ESP1 protein, S cerevisiae; D064247:Separase; D020123:Sirolimus
keywords: CVT pathway; DNA damage; GARP; anaphase; cell cycle checkpoint