Monopolin is a protein complex that in budding yeast is composed of the four proteins CSM1, HRR25, LRS4, and MAM1. Monopolin is required for the segregation of homologous centromeres to opposite poles of a dividing cell during anaphase I of meiosis.[1] This occurs by bridging DSN1 kinetochore proteins to sister kinetochores within the centromere to physically fuse them and allow for the microtubules to pull each homolog toward opposite mitotic spindles.[2]
Molecular structure
Monopolin is composed of a 4 CSM1:2 LRS4 complex which forms a V-shaped structure with two globular heads at the ends, which are responsible for directly crosslinking sister kinetochores.[1] Bound to each CSM1 head is a MAM1 protein which recruits one copy of the HRR25 kinase.[3] The hydrophobic cavity on the CSM1 subunit allows the hydrophobic regions of Monopolin receptor and kinetochore protein, DSN1, to bind to and fuse the sister kinetochores.[2] Microtubules can then attach to the kinetochores on the homologous centromeres and pull them toward opposite mitotic spindles to complete anaphase of meiosis I.
References
- ^ a b Corbett KD, Yip CK, Ee LS, Walz T, Amon A, Harrison SC (August 2010). "The monopolin complex crosslinks kinetochore components to regulate chromosome-microtubule attachments". Cell. 142 (4): 556–67. doi:10.1016/j.cell.2010.07.017. PMC 2955198. PMID 20723757.
- ^ a b Plowman, Rebecca; Singh, Namit; Tromer, Eelco C.; Payan, Angel; Duro, Eris; Spanos, Christos; Rappsilber, Juri; Snel, Berend; Kops, Geert J. P.L.; Corbett, Kevin D.; Marston, Adele L. (2019-09-01). "The molecular basis of monopolin recruitment to the kinetochore". Chromosoma. 128 (3): 331–354. doi:10.1007/s00412-019-00700-0. ISSN 1432-0886. PMC 6823300. PMID 31037469.
- ^ Corbett, Kevin D.; Harrison, Stephen C. (2012-06-28). "Molecular Architecture of the Yeast Monopolin Complex". Cell Reports. 1 (6): 583–589. doi:10.1016/j.celrep.2012.05.012. ISSN 2211-1247. PMC 3494995. PMID 22813733.