3si5

Structural highlights

Disease

[BUB1B_HUMAN] Mosaic variegated aneuploidy syndrome. Defects in BUB1B are associated with tumor formation. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. MVA1 is caused by biallelic mutations in the BUB1B gene. [CASC5_HUMAN] Autosomal recessive primary microcephaly. A chromosomal aberration involving CASC5 is associated with acute myeloblastic leukemia (AML). Translocation t(11;15)(q23;q14) with KMT2A/MLL1. May give rise to a KMT2A/MLL1-CASC5 fusion protein. The disease is caused by mutations affecting the gene represented in this entry.

Function

[BUB1B_HUMAN] Essential component of the mitotic checkpoint. Required for normal mitosis progression. The mitotic checkpoint delays anaphase until all chromosomes are properly attached to the mitotic spindle. One of its checkpoint functions is to inhibit the activity of the anaphase-promoting complex/cyclosome (APC/C) by blocking the binding of CDC20 to APC/C, independently of its kinase activity. The other is to monitor kinetochore activities that depend on the kinetochore motor CENPE. Required for kinetochore localization of CENPE. Negatively regulates PLK1 activity in interphase cells and suppresses centrosome amplification. Also implicated in triggering apoptosis in polyploid cells that exit aberrantly from mitotic arrest. May play a role for tumor suppression.^{[1] [2] [3] [4] [5] [6]} [CASC5_HUMAN] Performs two crucial functions during mitosis: it is essential for spindle-assembly checkpoint signaling and for correct chromosome alignment. Required for attachment of the kinetochores to the spindle microtubules. Directly links BUB1 and BUB1B to kinetochores. Part of the MIS12 complex, which may be fundamental for kinetochore formation and proper chromosome segregation during mitosis. Acts in coordination with CENPK to recruit the NDC80 complex to the outer kinetochore.^{[7] [8] [9]}

See Also

• Serine/threonine protein kinase

References

1. ↑ Chan GK, Jablonski SA, Sudakin V, Hittle JC, Yen TJ. Human BUBR1 is a mitotic checkpoint kinase that monitors CENP-E functions at kinetochores and binds the cyclosome/APC. J Cell Biol. 1999 Sep 6;146(5):941-54. PMID:10477750
2. ↑ Tang Z, Bharadwaj R, Li B, Yu H. Mad2-Independent inhibition of APCCdc20 by the mitotic checkpoint protein BubR1. Dev Cell. 2001 Aug;1(2):227-37. PMID:11702782
3. ↑ Shin HJ, Baek KH, Jeon AH, Park MT, Lee SJ, Kang CM, Lee HS, Yoo SH, Chung DH, Sung YC, McKeon F, Lee CW. Dual roles of human BubR1, a mitotic checkpoint kinase, in the monitoring of chromosomal instability. Cancer Cell. 2003 Dec;4(6):483-97. PMID:14706340
4. ↑ Johnson VL, Scott MI, Holt SV, Hussein D, Taylor SS. Bub1 is required for kinetochore localization of BubR1, Cenp-E, Cenp-F and Mad2, and chromosome congression. J Cell Sci. 2004 Mar 15;117(Pt 8):1577-89. PMID:15020684 doi:http://dx.doi.org/10.1242/jcs.01006
5. ↑ Park SY, Kim S, Cho H, Kwon SH, Chae S, Kang D, Seong YS, Cho H. Depletion of BubR1 promotes premature centrosomal localization of cyclin B1 and accelerates mitotic entry. Cell Cycle. 2009 Jun 1;8(11):1754-64. Epub 2009 Jun 4. PMID:19411850
6. ↑ Izumi H, Matsumoto Y, Ikeuchi T, Saya H, Kajii T, Matsuura S. BubR1 localizes to centrosomes and suppresses centrosome amplification via regulating Plk1 activity in interphase cells. Oncogene. 2009 Aug 6;28(31):2806-20. doi: 10.1038/onc.2009.141. Epub 2009 Jun 8. PMID:19503101 doi:http://dx.doi.org/10.1038/onc.2009.141
7. ↑ Obuse C, Iwasaki O, Kiyomitsu T, Goshima G, Toyoda Y, Yanagida M. A conserved Mis12 centromere complex is linked to heterochromatic HP1 and outer kinetochore protein Zwint-1. Nat Cell Biol. 2004 Nov;6(11):1135-41. Epub 2004 Oct 24. PMID:15502821 doi:http://dx.doi.org/10.1038/ncb1187
8. ↑ Kiyomitsu T, Obuse C, Yanagida M. Human Blinkin/AF15q14 is required for chromosome alignment and the mitotic checkpoint through direct interaction with Bub1 and BubR1. Dev Cell. 2007 Nov;13(5):663-76. PMID:17981135 doi:http://dx.doi.org/10.1016/j.devcel.2007.09.005
9. ↑ Cheeseman IM, Hori T, Fukagawa T, Desai A. KNL1 and the CENP-H/I/K complex coordinately direct kinetochore assembly in vertebrates. Mol Biol Cell. 2008 Feb;19(2):587-94. Epub 2007 Nov 28. PMID:18045986 doi:http://dx.doi.org/10.1091/mbc.E07-10-1051
10. ↑ Bolanos-Garcia VM, Lischetti T, Matak-Vinkovic D, Cota E, Simpson PJ, Chirgadze DY, Spring DR, Robinson CV, Nilsson J, Blundell TL. Structure of a Blinkin-BUBR1 Complex Reveals an Interaction Crucial for Kinetochore-Mitotic Checkpoint Regulation via an Unanticipated Binding Site. Structure. 2011 Oct 12. PMID:22000412 doi:10.1016/j.str.2011.09.017