Biology subjects

Pearl, L.

Publications and source records attributed to Pearl, L..

3 recordsLinked to original sources

bioRxiv2025

CCDC103-mediated assembly of the R2C complex links RUVBL1-RUVBL2 to Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a genetic disorder caused by defective cilia motility, powered by axonemal dynein motors. Assembly of these motors is facilitated by the molecular chaperone HSP90, its co-chaperone RUVBL1-RUVBL2 and adaptor proteins such as CCDC103 (aka DNAAF19). Mutations in CCDC103 identified in PCD patients impair dynein assembly, contributing to the disease pathology. Here, we present the cryo-electron microscopy structure of the human RUVBL1-RUVBL2-CCDC103 complex at 3.2[A] resolution, a chaperone assembly we refer to as R2C. It comprises a hetero-hexameric RUVBL1-RUVBL2 ring bound to three CCDC103 molecules via their RUVBL2-binding domains (RBDs), which have additional functions. Unlike RPAP3 of R2TP, a previously defined co-chaperone of HSP90, CCDC103 lacks a PIH1D1-binding motif and TPR domains, but its flexible N-terminal region regulates RUVBL1-RUVBL2 oligomerisation. Our characterisation of the R2C complex presented here enhances understanding of the intricate protein network involved in Hsp90-mediated assembly of dynein motors and how adaptor mutations contribute to PCD.

biochemistry↗

bioRxiv2022

HSP90-CDC37-PP5 forms a structural platform for kinase dephosphorylation

Activation of client protein kinases by the HSP90 molecular chaperone system is affected by phosphorylation at multiple sites on HSP90, on the kinase specific co-chaperone CDC37, and the kinase client itself. Removal of regulatory phosphorylation from client kinases and their release from the HSP90-CDC37 system depends on a Ser/Thr phosphatase PP5, which associates with HSP90 via its N-terminal TPR domain. Here we present the cryoEM structure of the oncogenic protein kinase client BRAFV600E bound to HSP90-CDC37, showing how the V600E mutation favours BRAF association with HSP90-CDC37. Structures of HSP90-CDC37-BRAFV600E complexes with PP5, in autoinhibited and activated conformations, together with proteomic analysis of its phosphatase activity, reveal how PP5 is activated by recruitment to HSP90 complexes to comprehensively dephosphorylate client proteins.

biochemistry↗

bioRxiv2018

N-terminal BRCT domains of the DNA damage checkpoint proteins TOPBP1/Rad4 display distinct specificities for phosphopeptide ligands

TOPBP1 and its fission yeast homologue Rad4, are critical players in a range of DNA replication, repair and damage signalling processes. They are composed of multiple BRCT domains, some of which have the capacity to bind phosphorylated motifs in other proteins. They thus act as multi-point adaptors bringing proteins together into functional combinations, dependent on post-translational modifications downstream of cell cycle and DNA damage signals. We have now structurally and/or biochemically characterised a sufficient number of high-affinity complexes for the conserved N-terminal region of TOPBP1 and Rad4 in complex with diverse phospho-ligands - which include human RAD9 and Treslin, as well as S.pombe Crb2 and Sld3 - to define the key determinants of BRCT domain specificity. We use this information to identify and characterise previously unknown phosphorylation-dependent TOPBP1/Rad4-binding motifs in human RHNO1 and the fission yeast homologue of MDC1, Mdb1. These results provide important insights into how multiple BRCT domains within TOPBP1/Rad4 achieve selective and combinatorial binding of their multiple partner proteins.

biochemistry↗