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Role of the Exocyst Complex Component Sec6/8 in Genomic Stability
Journal article   Peer reviewed

Role of the Exocyst Complex Component Sec6/8 in Genomic Stability

Michael J Torres, Raj K Pandita, Ozlem Kulak, Rakesh Kumar, Etienne Formstecher, Nobuo Horikoshi, Kalpana Mujoo, Clayton R Hunt, Yingming Zhao, Lawrence Lum, …
Molecular and cellular biology, Vol.35(21), pp.3633-3645
11/2015
DOI: 10.1128/MCB.00768-15
PMCID: PMC4589602
PMID: 26283729

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Abstract

The exocyst is a heterooctomeric complex well appreciated for its role in the dynamic assembly of specialized membrane domains. Accumulating evidence indicates that this macromolecular machine also serves as a physical platform that coordinates regulatory cascades supporting biological systems such as host defense signaling, cell fate, and energy homeostasis. The isolation of multiple components of the DNA damage response (DDR) as exocyst-interacting proteins, together with the identification of Sec8 as a suppressor of the p53 response, suggested functional interactions between the exocyst and the DDR. We found that exocyst perturbation resulted in resistance to ionizing radiation (IR) and accelerated resolution of DNA damage. This occurred at the expense of genomic integrity, as enhanced recombination frequencies correlated with the accumulation of aberrant chromatid exchanges. Sec8 perturbation resulted in the accumulation of ATF2 and RNF20 and the promiscuous accumulation of DDR-associated chromatin marks and Rad51 repairosomes. Thus, the exocyst supports DNA repair fidelity by limiting the formation of repair chromatin in the absence of DNA damage.
DNA Repair Beclin-1 Genomic Instability Vesicular Transport Proteins - metabolism Humans Apoptosis Regulatory Proteins - analysis Ubiquitin-Protein Ligases - metabolism Exocytosis Autophagy Activating Transcription Factor 2 - metabolism Membrane Proteins - analysis Apoptosis Regulatory Proteins - metabolism Gene Deletion Activating Transcription Factor 2 - analysis Ubiquitin-Protein Ligases - analysis Cell Line, Tumor Membrane Proteins - metabolism Tumor Suppressor p53-Binding Protein 1 Intracellular Signaling Peptides and Proteins - genetics Vesicular Transport Proteins - analysis

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