Kinetochore microtubules are known to be differentially stable to a variety of microtubule depolymerization agents compared to the non-kinetochore polar microtubules, but the dynamics of microtubule attachment to the kinetochore is currently controversial. We have examined the stability of kinetochore microtubules in metaphase PtK1 spindles at 23 degrees C when microtubule assembly is abruptly blocked with the drug nocodazole. Metaphase cells were incubated in medium containing 34 microM nocodazole for various times before fixation and processing either for immunofluorescence light microscopy or serial-section electron microscopy. Microtubules not associated with kinetochore fibers disappeared completely in less than 1 min. Kinetochore fibers persisted and shortened, as the spindle poles moved close to the chromosomes over a 10–20 min interval. During this shortening process, the number of kinetochore microtubules decreased slowly. The mean number of kinetochore microtubules was 24 +/− 5 in control cells and zero in cells incubated with nocodazole for 20 min. The half-time of microtubule attachment to the kinetochore was approximately 7.5 min. These results show that when microtubule assembly is blocked, kinetochore microtubules shorten more slowly and persist about 10 times longer than the labile polar microtubules. If kinetochore microtubules shorten by tubulin dissociation at their plus-ends like the non-kinetochore polar microtubules, then the microtubule surface lattice must be able to translocate through the kinetochore attachment site without frequent detachment occurring.
Stability of microtubule attachment to metaphase kinetochores in PtK1 cells
L. Cassimeris, C.L. Rieder, G. Rupp, E.D. Salmon; Stability of microtubule attachment to metaphase kinetochores in PtK1 cells. J Cell Sci 1 May 1990; 96 (1): 9–15. doi: https://doi.org/10.1242/jcs.96.1.9
Download citation file:
Advertisement
Cited by
2021 JCS Prize winner announced
-JCSPrize.png?versionId=3749)
We are pleased to announce that the winner of the 2021 JCS Prize is Lee Dolat for his paper entitled ‘An endometrial organoid model of interactions between Chlamydia and epithelial and immune cells’.
Propose a new Workshop
-GSWorkshop.png?versionId=3749)
Our Workshops bring together leading experts and early-career researchers from a range of scientific backgrounds. Applications are now open to propose Workshops for 2024, one of which will be held in a Global South country.
Cell scientist to watch: Christian Münch
-CSTW.png?versionId=3749)
Journal of Cell Science interviewed Christian Münch, who established his independent research group in 2016 at Goethe University Frankfurt. His lab studies cellular stress responses to mitochondrial protein misfolding, infection and disease, as well as developing proteomics methods.
Essay series: Equity, diversity and inclusion in cell biology
-EssaySeries.png?versionId=3749)
The JCS Essay Series is an initiative to help showcase and provide a platform for voices in the field of cell biology. The first topic we covered was 'Equity, diversity and inclusion in cell biology', and the winning and runner up essays are now available to read.
FocalPlane Network launched
-FocalPlaneNetworkLaunch.png?versionId=3749)
We are excited to announce the launch of the FocalPlane Network, an international directory of microscopists. The idea behind the FocalPlane Network is to facilitate promotion and networking as well as assist those seeking conference speakers, committee members, reviewers or collaborators. We hope that it will help promote diversity in the community. Find out more and join the Network here.