Abstract
We have analyzed the mitotic function of SENP6, a small ubiquitin-like modifier (SUMO) protease that disassembles conjugated SUMO-2/3 chains. Cells lacking SENP6 showed defects in spindle assembly and metaphase chromosome congression. Analysis of kinetochore composition in these cells revealed that a subset of proteins became undetectable on inner kinetochores after SENP6 depletion, particularly the CENP-H/I/K complex, whereas other changes in kinetochore composition mimicked defects previously reported to result from CENP-H/I/K depletion. We further found that CENP-I is degraded through the action of RNF4, a ubiquitin ligase which targets polysumoylated proteins for proteasomal degradation, and that SENP6 stabilizes CENP-I by antagonizing RNF4. Together, these findings reveal a novel mechanism whereby the finely balanced activities of SENP6 and RNF4 control vertebrate kinetochore assembly through SUMO-targeted destabilization of inner plate components.
Publication types
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Research Support, N.I.H., Intramural
MeSH terms
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Animals
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Aurora Kinases
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Chromosomes / metabolism
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Cysteine Endopeptidases / genetics
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Cysteine Endopeptidases / metabolism*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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HeLa Cells
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Histones / genetics
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Histones / metabolism
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Humans
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Kinetochores / metabolism*
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Kinetochores / ultrastructure
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Microtubules / metabolism
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Mitosis / physiology*
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Multiprotein Complexes / metabolism
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Protein Serine-Threonine Kinases / metabolism
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RNA, Small Interfering / genetics
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RNA, Small Interfering / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Spindle Apparatus / metabolism*
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Transcription Factors / genetics
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Transcription Factors / metabolism
Substances
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DNA-Binding Proteins
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Histones
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Multiprotein Complexes
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Nuclear Proteins
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RNA, Small Interfering
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RNF4 protein, human
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Recombinant Fusion Proteins
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Transcription Factors
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Aurora Kinases
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Protein Serine-Threonine Kinases
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Cysteine Endopeptidases
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SENP6 protein, human