Hsp110 is required for spindle length control.
Systematic affinity purification combined with mass spectrometry analysis of N- and C-tagged cytoplasmic Hsp70/Hsp110 chaperones was used to identify new roles of Hsp70/Hsp110 in the cell. This allowed the mapping of a chaperone-protein network consisting of 1,227 unique interactions between the 9 chaperones and 473 proteins and highlighted roles for Hsp70/Hsp110 in 14 broad biological processes. Using this information, we uncovered an essential role for Hsp110 in spindle assembly and, more specifically, in modulating the activity of the widely conserved kinesin-5 motor Cin8. The role of Hsp110 Sse1 as a nucleotide exchange factor for the Hsp70 chaperones Ssa1/Ssa2 was found to be required for maintaining the proper distribution of kinesin-5 motors within the spindle, which was subsequently required for bipolar spindle assembly in S phase. These data suggest a model whereby the Hsp70-Hsp110 chaperone complex antagonizes Cin8 plus-end motility and prevents premature spindle elongation in S phase.
Department of Biochemistry, Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
Taras
T
Makhnevych
Philip
P
Wong
Oxana
O
Pogoutse
Franco J
FJ
Vizeacoumar
Jack F
JF
Greenblatt
Andrew
A
Emili
Walid A
WA
Houry
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D020662:Guanine Nucleotide Exchange Factors / Q000502:physiology; D050957:HSP110 Heat-Shock Proteins / Q000502:physiology*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D016547:Kinesins / Q000378:metabolism / Q000502:physiology; D020409:Molecular Motor Proteins / Q000378:metabolism; D016196:S Phase / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000502:physiology*
C075342:CIN8 protein, S cerevisiae; D020662:Guanine Nucleotide Exchange Factors; D050957:HSP110 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D020409:Molecular Motor Proteins; C542288:SSA2 protein, S cerevisiae; C494656:SSE1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; C095973:SSA1 protein, S cerevisiae; D016547:Kinesins