1. Yeast Sphingolipid Phospholipase Gene ISC1 Regulates the Spindle Checkpoint by a CDC55 -Dependent Mechanism.
- Author
-
Matmati N, Hassan BH, Ren J, Shamssedine AA, Jeong E, Shariff B, Snider J, Rødkær SV, Chen G, Mohanty BK, Zheng WJ, Obeid LM, Røssel-Larsen M, Færgeman NJ, and Hannun YA
- Subjects
- Cell Cycle, Cell Cycle Proteins metabolism, Chromosome Segregation, Chromosomes, Fungal genetics, Chromosomes, Fungal metabolism, Gene Deletion, Gene Regulatory Networks, Genes, Fungal, Protein Phosphatase 2 metabolism, Saccharomyces cerevisiae cytology, Saccharomyces cerevisiae metabolism, Saccharomyces cerevisiae Proteins metabolism, Spindle Apparatus genetics, Spindle Apparatus metabolism, Type C Phospholipases metabolism, Cell Cycle Proteins genetics, Gene Expression Regulation, Fungal, Protein Phosphatase 2 genetics, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae Proteins genetics, Type C Phospholipases genetics
- Abstract
Defects in the spindle assembly checkpoint (SAC) can lead to aneuploidy and cancer. Sphingolipids have important roles in many cellular functions, including cell cycle regulation and apoptosis. However, the specific mechanisms and functions of sphingolipids in cell cycle regulation have not been elucidated. Using analysis of concordance for synthetic lethality for the yeast sphingolipid phospholipase ISC1 , we identified two groups of genes. The first comprises genes involved in chromosome segregation and stability ( CSM3 , CTF4 , YKE2 , DCC1 , and GIM4 ) as synthetically lethal with ISC1 The second group, to which ISC1 belongs, comprises genes involved in the spindle checkpoint ( BUB1 , MAD1 , BIM1 , and KAR3 ), and they all share the same synthetic lethality with the first group. We demonstrate that spindle checkpoint genes act upstream of Isc1, and their deletion phenocopies that of ISC1 Reciprocally, ISC1 deletion mutants were sensitive to benomyl, indicating a SAC defect. Similar to BUB1 deletion, ISC1 deletion prevents spindle elongation in hydroxyurea-treated cells. Mechanistically, PP2A-Cdc55 ceramide-activated phosphatase was found to act downstream of Isc1, thus coupling the spindle checkpoint genes and Isc1 to CDC55 -mediated nuclear functions., (Copyright © 2020 American Society for Microbiology.)
- Published
- 2020
- Full Text
- View/download PDF