title: Retinoblastoma protein enhances the fidelity of chromosome segregation mediated by hsHec1p.
abstract: Retinoblastoma protein (Rb) plays important roles in cell cycle progression and cellular differentiation. It may also participate in M phase events, although heretofore only circumstantial evidence has suggested such involvement. Here we show that Rb interacts, through an IxCxE motif and specifically during G(2)/M phase, with hsHec1p, a protein essential for proper chromosome segregation. The interaction between Rb and hsHec1p was reconstituted in a yeast strain in which human hsHEC1 rescues the null mutation of scHEC1. Expression of Rb reduced chromosome segregation errors fivefold in yeast cells sustained by a temperature-sensitive (ts) hshec1-113 allele and enhanced the ability of wild-type hsHec1p to suppress lethality caused by a ts smc1 mutation. The interaction between Hec1p and Smc1p was important for the specific DNA-binding activity of Smc1p. Expression of Rb restored part of the inactivated function of hshec1-113p and thereby increased the DNA-binding activity of Smc1p. Rb thus increased the fidelity of chromosome segregation mediated by hsHec1p in a heterologous yeast system.
authors.affiliation: Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78245, USA.
authors.forename: L
authors.initials: L
authors.lastname: Zheng
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: D J
authors.initials: DJ
authors.lastname: Riley
authors.forename: P L
authors.initials: PL
authors.lastname: Chen
authors.forename: W H
authors.initials: WH
authors.lastname: Lee
mesh_terms: D020816:Amino Acid Motifs; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone; D020090:Chromosome Segregation; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D016195:G2 Phase; D005804:Genes, Lethal; D008938:Mitosis; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics; D013489:Suppression, Genetic; D000098550:Structural Maintenance of Chromosome Protein 1
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C120529:NDC80 protein, human; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D016160:Retinoblastoma Protein; D000098550:Structural Maintenance of Chromosome Protein 1