The major focus for the next period of this grant will be spindle, kinetochore and centromere protein mechanisms that act to achieve accurate chromosome segregation. Accuracy is critical because the mis- segregation of even one chromosome produces aneuploidy that can lead to cancer or developmental defects. Kinetochores have at least five key roles in assuring accurate segregation: 1) they produce a diffusible signal for the spindle checkpoint to delay anaphase until sister kinetochores are properly attached by MTs to opposite poles and aligned on the metaphase plate;2) they provide stable, but dynamic, attachment to MT plus ends to turn off spindle checkpoint activity and prevent errors in MT attachment;3) they act as a force- generating depolymerase for movement of chromosomes poleward coupled to plus-end depolymerization of kMTs at the kinetochore;4) they provide a tension-sensitive slip clutch, generating tension from the poleward flux of kMTs while maintaining attachment to polymerizing plus ends of MTs during kinetochore movements away from the pole, and 5) they correct errors in MT attachment so that the formation of kMTs to opposite poles (merotelic orientation) does not result in lagging chromosomes and mis-segregation in anaphase. Centromere passenger proteins, which are located on the inner centromere behind the kinetochore, also appear to regulate kMT attachment and MT-dependent signaling of the cortical site for cytokinesis. Most of our studies focus on protein function in mammalian tissue cells, but budding yeast mitotic kinetochores and shmoo tips are useful genetic models for understanding protein function at dynamic plus-end attachment sites. A major strength of our program has been, and will continue to be, the development and application of new microscopy techniques for measurements of protein function in living cells and reconstituted preparations.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37GM024364-34
Application #
8242098
Study Section
Special Emphasis Panel (NSS)
Program Officer
Gindhart, Joseph G
Project Start
1978-09-01
Project End
2014-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
34
Fiscal Year
2012
Total Cost
$362,637
Indirect Cost
$117,612
Name
University of North Carolina Chapel Hill
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Suzuki, Aussie; Badger, Benjamin L; Haase, Julian et al. (2016) How the kinetochore couples microtubule force and centromere stretch to move chromosomes. Nat Cell Biol 18:382-92
Suzuki, Aussie; Badger, Benjamin L; Salmon, Edward D (2015) A quantitative description of Ndc80 complex linkage to human kinetochores. Nat Commun 6:8161
Suzuki, Aussie; Badger, Benjamin L; Wan, Xiaohu et al. (2014) The architecture of CCAN proteins creates a structural integrity to resist spindle forces and achieve proper Intrakinetochore stretch. Dev Cell 30:717-30
Varma, Dileep; Wan, Xiaohu; Cheerambathur, Dhanya et al. (2013) Spindle assembly checkpoint proteins are positioned close to core microtubule attachment sites at kinetochores. J Cell Biol 202:735-46
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Varma, Dileep; Chandrasekaran, Srikripa; Sundin, Lynsie J R et al. (2012) Recruitment of the human Cdt1 replication licensing protein by the loop domain of Hec1 is required for stable kinetochore-microtubule attachment. Nat Cell Biol 14:593-603
Wan, Xiaohu; Cimini, Daniela; Cameron, Lisa A et al. (2012) The coupling between sister kinetochore directional instability and oscillations in centromere stretch in metaphase PtK1 cells. Mol Biol Cell 23:1035-46
Dumont, Sophie; Salmon, E D; Mitchison, Timothy J (2012) Deformations within moving kinetochores reveal different sites of active and passive force generation. Science 337:355-8
Varma, Dileep; Salmon, E D (2012) The KMN protein network--chief conductors of the kinetochore orchestra. J Cell Sci 125:5927-36
Lawrimore, Josh; Bloom, Kerry S; Salmon, E D (2011) Point centromeres contain more than a single centromere-specific Cse4 (CENP-A) nucleosome. J Cell Biol 195:573-82

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