title: Mechanisms of functional promiscuity by HP1 proteins.
abstract: Heterochromatin protein 1 (HP1) proteins were originally identified as critical components in heterochromatin-mediated gene silencing and are now recognized to play essential roles in several other processes including gene activation. Several eukaryotes possess more than one HP1 paralog. Despite high sequence conservation, the HP1 paralogs achieve diverse functions. Further, in many cases, the same HP1 paralog is implicated in multiple functions. Recent biochemical studies have revealed interesting paralog-specific biophysical differences and unanticipated conformational versatility in HP1 proteins that may account for this functional promiscuity. Here we review these findings and describe a molecular framework that aims to link the conformational flexibility of HP1 proteins observed in vitro with their functional promiscuity observed in vivo.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
authors.forename: Daniele
authors.initials: D
authors.lastname: Canzio
authors.affiliation: Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158, USA; Tetrad Graduate Program, University of California San Francisco, San Francisco, CA 94158, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Larson
authors.affiliation: Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158, USA. Electronic address: geeta.narlikar@ucsf.edu.
authors.forename: Geeta J
authors.initials: GJ
authors.lastname: Narlikar
mesh_terms: D000818:Animals; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000378:metabolism*; D056890:Eukaryota / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009707:Nucleosomes / Q000378:metabolism
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D009707:Nucleosomes; D000090266:Chromobox Protein Homolog 5
keywords: HP1; chromatin; conformational flexibility; functional versatility