title: Structure of the polycomb group protein PCGF1 in complex with BCOR reveals basis for binding selectivity of PCGF homologs.
abstract: Polycomb-group RING finger homologs (PCGF1, PCGF2, PCGF3, PCGF4, PCGF5, and PCGF6) are critical components in the assembly of distinct Polycomb repression complex 1 (PRC1)-related complexes. Here, we identify a protein interaction domain in BCL6 corepressor, BCOR, which binds the RING finger- and WD40-associated ubiquitin-like (RAWUL) domain of PCGF1 (NSPC1) and PCGF3 but not of PCGF2 (MEL18) or PCGF4 (BMI1). Because of the selective binding, we have named this domain PCGF Ub-like fold discriminator (PUFD). The structure of BCOR PUFD bound to PCGF1 reveals that (1) PUFD binds to the same surfaces as observed for a different Polycomb group RAWUL domain and (2) the ability of PUFD to discriminate among RAWULs stems from the identity of specific residues within these interaction surfaces. These data show the molecular basis for determining the binding preference for a PCGF homolog, which ultimately helps determine the identity of the larger PRC1-like assembly.
authors.affiliation: Department of Biochemistry and CTRC, University of Texas Health Science Center at San Antonio, MSC 7760, 7703 Floyd Curl Drive, San Antonio, TX 78229-3990, USA.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Junco
authors.forename: Renjing
authors.initials: R
authors.lastname: Wang
authors.forename: John C
authors.initials: JC
authors.lastname: Gaipa
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Taylor
authors.forename: Virgil
authors.initials: V
authors.lastname: Schirf
authors.forename: Micah D
authors.initials: MD
authors.lastname: Gearhart
authors.forename: Vivian J
authors.initials: VJ
authors.lastname: Bardwell
authors.forename: Borries
authors.initials: B
authors.lastname: Demeler
authors.forename: P John
authors.initials: PJ
authors.lastname: Hart
authors.forename: Chongwoo A
authors.initials: CA
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D003460:Crystallization; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000378:metabolism; D063150:Polycomb Repressive Complex 1 / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity; D014461:Ultracentrifugation
chemical_list: C411984:BCOR protein, human; D046912:Multiprotein Complexes; C496334:PCGF1 protein, human; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1