Hsk1-Dfp1 is required for heterochromatin-mediated cohesion at centromeres.
Heterochromatin performs a central role in chromosome segregation and stability by promoting cohesion at centromeres. Establishment of both heterochromatin-mediated silencing and cohesion requires passage through S phase, although the mechanism is unknown. Here we demonstrate that Schizosaccharomyces pombe Hsk1 (CDC7), a conserved Dbf4-dependent protein kinase (DDK) that regulates replication initiation, interacts with and phosphorylates the heterochromatin protein 1 (HP1) equivalent Swi6 (ref. 6). Hsk1 and its regulatory subunit Dfp1 function downstream of Swi6 localization to promote heterochromatin function and cohesion specifically at centromeres. This role for Hsk1-Dfp1 is separable from its replication initiation activity, providing a temporal link between S phase and centromere cohesion that is mediated by heterochromatin.
Bailis
Julie M
JM
Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
Bernard
Pascal
P
Antonelli
Richard
R
Allshire
Robin C
RC
Forsburg
Susan L
SL
D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000235:genetics*; D002503:Centromere / Q000235:genetics*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D020090:Chromosome Segregation / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics; D006570:Heterochromatin / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000235:genetics; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D006570:Heterochromatin; D021122:Protein Subunits; D029702:Schizosaccharomyces pombe Proteins; C465958:Swi6 protein, S pombe; C094761:HSK1 protein, S pombe; D017346:Protein Serine-Threonine Kinases