Abstract
Nucleosomes containing the histone H3 variant CENP-A are the epigenetic mark of centromeres, the kinetochore assembly sites required for chromosome segregation. HJURP is the CENP-A chaperone, which associates with Mis18α, Mis18β, and M18BP1 to target centromeres and deposit new CENP-A. How these proteins interact to promote CENP-A deposition remains poorly understood. Here we show that two repeats in human HJURP proposed to be functionally distinct are in fact interchangeable and bind concomitantly to the 4:2:2 Mis18α:Mis18β:M18BP1 complex without dissociating it. HJURP binds CENP-A:H4 dimers, and therefore assembly of CENP-A:H4 tetramers must be performed by two Mis18αβ:M18BP1:HJURP complexes, or by the same complex in consecutive rounds. The Mis18α N-terminal tails blockade two identical HJURP-repeat binding sites near the Mis18αβ C-terminal helices. These were identified by photo-cross-linking experiments and mutated to separate Mis18 from HJURP centromere recruitment. Our results identify molecular underpinnings of eukaryotic chromosome inheritance and shed light on how centromeres license CENP-A deposition.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing / chemistry
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Adaptor Proteins, Signal Transducing / genetics
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Adaptor Proteins, Signal Transducing / metabolism*
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Amino Acid Sequence
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Binding Sites
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Cell Cycle Proteins / chemistry
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Centromere / metabolism*
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Centromere Protein A / chemistry
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Centromere Protein A / genetics
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Centromere Protein A / metabolism*
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Chromosomal Proteins, Non-Histone / chemistry
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Chromosomal Proteins, Non-Histone / genetics
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Chromosomal Proteins, Non-Histone / metabolism*
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DNA-Binding Proteins / chemistry
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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 / chemistry
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Histones / metabolism*
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Humans
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Molecular Chaperones / chemistry
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Molecular Chaperones / genetics
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Molecular Chaperones / metabolism*
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Protein Binding
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RNA Interference
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Sequence Homology, Amino Acid
Substances
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Adaptor Proteins, Signal Transducing
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Cell Cycle Proteins
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Centromere Protein A
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Chromosomal Proteins, Non-Histone
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DNA-Binding Proteins
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HJURP protein, human
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Histones
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MIS18A protein, human
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Molecular Chaperones
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OIP5 protein, human