title: Structure of the human cohesin inhibitor Wapl.
abstract: Cohesin, along with positive regulators, establishes sister-chromatid cohesion by forming a ring to circle chromatin. The wings apart-like protein (Wapl) is a key negative regulator of cohesin and forms a complex with precocious dissociation of sisters protein 5 (Pds5) to promote cohesin release from chromatin. Here we report the crystal structure and functional characterization of human Wapl. Wapl contains a flexible, variable N-terminal region (Wapl-N) and a conserved C-terminal domain (Wapl-C) consisting of eight HEAT (Huntingtin, Elongation factor 3, A subunit, and target of rapamycin) repeats. Wapl-C folds into an elongated structure with two lobes. Structure-based mutagenesis maps the functional surface of Wapl-C to two distinct patches (I and II) on the N lobe and a localized patch (III) on the C lobe. Mutating critical patch I residues weaken Wapl binding to cohesin and diminish sister-chromatid resolution and cohesin release from mitotic chromosomes in human cells and Xenopus egg extracts. Surprisingly, patch III on the C lobe does not contribute to Wapl binding to cohesin or its known regulators. Although patch I mutations reduce Wapl binding to intact cohesin, they do not affect Wapl-Pds5 binding to the cohesin subcomplex of sister chromatid cohesion protein 1 (Scc1) and stromal antigen 2 (SA2) in vitro, which is instead mediated by Wapl-N. Thus, Wapl-N forms extensive interactions with Pds5 and Scc1-SA2. Wapl-C interacts with other cohesin subunits and possibly unknown effectors to trigger cohesin release from chromatin.
authors.affiliation: Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: Zhuqing
authors.initials: Z
authors.lastname: Ouyang
authors.forename: Ge
authors.initials: G
authors.lastname: Zheng
authors.forename: Jianhua
authors.initials: J
authors.lastname: Song
authors.forename: Dominika M
authors.initials: DM
authors.lastname: Borek
authors.forename: Zbyszek
authors.initials: Z
authors.lastname: Otwinowski
authors.forename: Chad A
authors.initials: CA
authors.lastname: Brautigam
authors.forename: Diana R
authors.initials: DR
authors.lastname: Tomchick
authors.forename: Susannah
authors.initials: S
authors.lastname: Rankin
authors.forename: Hongtao
authors.initials: H
authors.lastname: Yu
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D009154:Mutation; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000235:genetics; D000097722:Cohesins
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D000097722:Cohesins; C488092:WAPL protein, human
keywords: chromosome segregation; crystallography; genomic stability; mitosis; protein–protein interaction