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Targeting Phosphopeptide Recognition by the Human BRCA1 Tandem BRCT Domain to Interrupt BRCA1-Dependent Signaling.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Periasamy, Jayaprakash 
Kurdekar, Vadiraj 
Jasti, Subbarao 
Nijaguna, Mamatha B 
Boggaram, Sanjana 

Abstract

Intracellular signals triggered by DNA breakage flow through proteins containing BRCT (BRCA1 C-terminal) domains. This family, comprising 23 conserved phosphopeptide-binding modules in man, is inaccessible to small-molecule chemical inhibitors. Here, we develop Bractoppin, a drug-like inhibitor of phosphopeptide recognition by the human BRCA1 tandem (t)BRCT domain, which selectively inhibits substrate binding with nanomolar potency in vitro. Structure-activity exploration suggests that Bractoppin engages BRCA1 tBRCT residues recognizing pSer in the consensus motif, pSer-Pro-Thr-Phe, plus an abutting hydrophobic pocket that is distinct in structurally related BRCT domains, conferring selectivity. In cells, Bractoppin inhibits substrate recognition detected by Förster resonance energy transfer, and diminishes BRCA1 recruitment to DNA breaks, in turn suppressing damage-induced G2 arrest and assembly of the recombinase, RAD51. But damage-induced MDC1 recruitment, single-stranded DNA (ssDNA) generation, and TOPBP1 recruitment remain unaffected. Thus, an inhibitor of phosphopeptide recognition selectively interrupts BRCA1 tBRCT-dependent signals evoked by DNA damage.

Description

Keywords

BRCA1, BRCT domain, DNA damage response, drug-like inhibitor, lead discovery, structure-activity relationship, BRCA1 Protein, Cell Survival, Cells, Cultured, Fluorescence Resonance Energy Transfer, HEK293 Cells, Humans, Molecular Dynamics Simulation, Molecular Structure, Phosphopeptides, Protein Domains, Signal Transduction, Structure-Activity Relationship

Journal Title

Cell Chem Biol

Conference Name

Journal ISSN

2451-9456
2451-9448

Volume Title

25

Publisher

Elsevier BV
Sponsorship
MRC (MR/N501876/1)