Rad5 and Its Human Homologs, HLTF and SHPRH, Are Novel Interactors of Mismatch Repair

Anna K. Miller, Guogen Mao, Breanna G. Knicely, Hannah G. Daniels, Christine Rahal, Christopher D. Putnam, Richard D. Kolodner, Eva M. Goellner

Research output: Contribution to journalArticlepeer-review

Abstract

DNA mismatch repair (MMR) repairs replication errors, and MMR defects play a role in both inherited cancer predisposition syndromes and in sporadic cancers. MMR also recognizes mispairs caused by environmental and chemotherapeutic agents; however, in these cases mispair recognition leads to apoptosis and not repair. Although mutation avoidance by MMR is fairly well understood, MMR-associated proteins are still being identified. We performed a bioinformatic analysis that implicated Saccharomyces cerevisiae Rad5 as a candidate for interacting with the MMR proteins Msh2 and Mlh1. Rad5 is a DNA helicase and E3 ubiquitin ligase involved in post-replicative repair and damage tolerance. We confirmed both interactions and found that the Mlh1 interaction is mediated by a conserved Mlh1-interacting motif (MIP box). Despite this, we did not find a clear role for Rad5 in the canonical MMR mutation avoidance pathway. The interaction of Rad5 with Msh2 and Mlh1 is conserved in humans, although each of the Rad5 human homologs, HLTF and SHPRH, shared only one of the interactions: HLTF interacts with MSH2, and SHPRH interacts with MLH1. Moreover, depletion of SHPRH, but not HLTF, results in a mild increase in resistance to alkylating agents although not as strong as loss of MMR, suggesting gene duplication led to specialization of the MMR-protein associated roles of the human Rad5 homologs. These results provide insights into how MMR accessory factors involved in the MMR-dependent apoptotic response interact with the core MMR machinery and have important health implications into how human cells respond to environmental toxins, tumor development, and treatment choices of tumors with defects in Rad5 homologs.

Original languageEnglish
Article number843121
JournalFrontiers in Cell and Developmental Biology
Volume10
DOIs
StatePublished - Jun 16 2022

Bibliographical note

Funding Information:
This publication was supported by a NIH grant R00ES026653, a Markey Foundation Markey Women Strong Distinguished Researcher award, and a Phi Beta Psi Cancer Research Grant to EG and NIH R01 GM50006 to RK and support from the Ludwig Institute for Cancer Research. This publication was also supported by UK-CARES through Grant P30 ES026529 as a Career Development Award to EG. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS. This research was supported by the Flow Cytometry and Immune Monitoring Core Shared Resource of the University of Kentucky Markey Cancer Center (P30CA177558).

Funding Information:
This publication was supported by a NIH grant R00ES026653, a Markey Foundation Markey Women Strong Distinguished Researcher award, and a Phi Beta Psi Cancer Research Grant to EG and NIH R01 GM50006 to RK and support from the Ludwig Institute for Cancer Research. This publication was also supported by UK-CARES through Grant P30 ES026529 as a Career Development Award to EG. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS. This research was supported by the Flow Cytometry and Immune Monitoring Core Shared Resource of the University of Kentucky Markey Cancer Center (P30CA177558).

Publisher Copyright:
Copyright © 2022 Miller, Mao, Knicely, Daniels, Rahal, Putnam, Kolodner and Goellner.

Keywords

  • alkylating agent MNNG
  • binding motif
  • HLTF
  • mismatch repair (MMR)
  • rad5
  • SHPRH

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology

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