Mis16 Independently Recognizes Histone H4 and the CENP-ACnp1-Specific Chaperone Scm3sp.
CENP-A is a centromere-specific histone H3 variant that is required for kinetochore assembly and accurate chromosome segregation. For it to function properly, CENP-A must be specifically localized to centromeres. In fission yeast, Scm3sp and the Mis18 complex, composed of Mis16, Eic1, and Mis18, function as a CENP-A(Cnp1)-specific chaperone and a recruiting factor, respectively, and together ensure accurate delivery of CENP-A(Cnp1) to centromeres. Although how Scm3sp specifically recognizes CENP-A(Cnp1) has been revealed recently, the recruiting mechanism of CENP-A(Cnp1) via the Mis18 complex remains unknown. In this study, we have determined crystal structures of Schizosaccharomyces japonicus Mis16 alone and in complex with the helix 1 of histone H4 (H4α1). Crystal structures followed by mutant analysis and affinity pull-downs have revealed that Mis16 recognizes both H4α1 and Scm3sp independently within the CENP-A(Cnp1)/H4:Scm3sp complex. This observation suggests that Mis16 gains CENP-A(Cnp1) specificity by recognizing both Scm3sp and histone H4. Our studies provide insights into the molecular mechanisms underlying specific recruitment of CENP-A(Cnp1)/H4:Scm3sp into centromeres.
Department of Biological Chemistry, University of Michigan Medical School, 1150 West Medical Center Drive, SPC 5606, Ann Arbor, MI 48109, USA.
Sojin
S
An
Department of Biological Chemistry, University of Michigan Medical School, 1150 West Medical Center Drive, SPC 5606, Ann Arbor, MI 48109, USA.
Hanseong
H
Kim
Department of Biological Chemistry, University of Michigan Medical School, 1150 West Medical Center Drive, SPC 5606, Ann Arbor, MI 48109, USA. Electronic address: uhnsoo@med.umich.edu.
Uhn-Soo
US
Cho
D001324:Autoantigens / Q000378:metabolism*; D002352:Carrier Proteins / Q000648:ultrastructure*; D002503:Centromere / Q000378:metabolism; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006657:Histones / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces
D001324:Autoantigens; D002352:Carrier Proteins; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D018832:Molecular Chaperones
Dual recognition; Histone chaperone; Kinetochore; The Mis18 complex; X-ray crystallography