Kinetochore

kinetochores
A kinetochore is a disc-shaped protein structure associated with duplicated chromatids in eukaryotic cells where the spindle fibers attach during cell division to pull sister chromatids apart.wikipedia
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Centromere

acrocentricsubmetacentricmetacentric
The kinetochore assembles on the centromere and links the chromosome to microtubule polymers from the mitotic spindle during mitosis and meiosis.
During mitosis, spindle fibers attach to the centromere via the kinetochore.

Spindle apparatus

mitotic spindlespindlespindle pole
The kinetochore assembles on the centromere and links the chromosome to microtubule polymers from the mitotic spindle during mitosis and meiosis. A kinetochore is a disc-shaped protein structure associated with duplicated chromatids in eukaryotic cells where the spindle fibers attach during cell division to pull sister chromatids apart.
Attachment of microtubules to chromosomes is mediated by kinetochores, which actively monitor spindle formation and prevent premature anaphase onset.

Metaphase

chromosomal misalignmentMM-phase
Following the transition from metaphase to anaphase, the sister chromatids separate from each other, and the individual kinetochores on each chromatid drive their movement to the spindle poles that will define the two new daughter cells.
Preceded by events in prometaphase and followed by anaphase, microtubules formed in prophase have already found and attached themselves to kinetochores in metaphase.

Chromosome

chromosomeschromosomalChromosomal number
Its proteins also help to hold the sister chromatids together and play a role in chromosome editing. In some areas in Asia however, the word is pronounced "connect-a-core", as it connects to the core of the chromosome.
During mitosis, microtubules grow from centrosomes located at opposite ends of the cell and also attach to the centromere at specialized structures called kinetochores, one of which is present on each sister chromatid.

Mitosis

mitoticmitosesmitotic division
The kinetochore assembles on the centromere and links the chromosome to microtubule polymers from the mitotic spindle during mitosis and meiosis.
In late prometaphase, kinetochore microtubules begin to search for and attach to chromosomal kinetochores.

Anaphase

Following the transition from metaphase to anaphase, the sister chromatids separate from each other, and the individual kinetochores on each chromatid drive their movement to the spindle poles that will define the two new daughter cells.
While the chromosomes are drawn to each side of the cell, the non-kinetochore spindle fibers push against each other, in a ratcheting action, that stretches the cell into an oval.

Meiosis

meioticsyzygymeiosis I
The kinetochore assembles on the centromere and links the chromosome to microtubule polymers from the mitotic spindle during mitosis and meiosis.
The microtubules invade the nuclear region after the nuclear envelope disintegrates, attaching to the chromosomes at the kinetochore.

Mad2

Other proteins, such as Mad2, monitor the microtubule attachment as well as the tension between sister kinetochores and activate the spindle checkpoint to arrest the cell cycle when either of these is absent. The dynamic components that vary in concentration on kinetochores during mitosis include the molecular motors CENP-E and dynein (as well as their target components ZW10 and ROD), and the spindle checkpoint proteins (such as Mad1, Mad2, BubR1 and Cdc20). These proteins assemble on the kinetochore in high concentrations in the absence of microtubules; however, the higher the number of MTs anchored to the kinetochore, the lower the concentrations of these proteins. At metaphase, CENP-E, Bub3 and Bub1 levels diminish by a factor of about three to four as compared with free kinetochores, whereas dynein/dynactin, Mad1, Mad2 and BubR1 levels are reduced by a factor of more than 10 to 100.
The human orthologues of Mad2 (MAD2L1 and MAD2L2) were first cloned in a search for human cDNAs that would rescue the microtubule poison-sensitivity of a yeast strain in which a kinetochore binding protein was missing.

CENPH

CENP-H
The first protein to be assembled on the kinetochore is CENP-A (Cse4 in Saccharomyces cerevisiae). This protein is a specialized isoform of histone H3. CENP-A is required for incorporation of the inner kinetochore proteins CENP-C, CENP-H and CENP-I/MIS6.
Centromere and kinetochore proteins play a critical role in centromere structure, kinetochore formation, and sister chromatid separation.

NDC80

Ndc80/Hec1
Proteins whose levels remain stable from prophase until late anaphase include constitutive components of the inner plate and the stable components of the outer kinetocore, such as the Ndc80 complex, KNL/KBP proteins (kinetochore-null/KNL-binding protein), MIS proteins and CENP-F. Together with the constitutive components, these proteins seem to organize the nuclear core of the inner and outer structures in the kinetochore.
Ndc80 is one of the proteins of outer kinetochore.

Cell cycle

cell-cyclecell division cyclecell cycle progression
an inner kinetochore, which is tightly associated with the centromere DNA and assembled in a specialized form of chromatin that persists throughout the cell cycle;
A critical complex activated during this process is a ubiquitin ligase known as the anaphase-promoting complex (APC), which promotes degradation of structural proteins associated with the chromosomal kinetochore.

Spindle checkpoint

spindle assembly checkpointbipolar orientationbipolarity
Other proteins, such as Mad2, monitor the microtubule attachment as well as the tension between sister kinetochores and activate the spindle checkpoint to arrest the cell cycle when either of these is absent. The dynamic components that vary in concentration on kinetochores during mitosis include the molecular motors CENP-E and dynein (as well as their target components ZW10 and ROD), and the spindle checkpoint proteins (such as Mad1, Mad2, BubR1 and Cdc20). These proteins assemble on the kinetochore in high concentrations in the absence of microtubules; however, the higher the number of MTs anchored to the kinetochore, the lower the concentrations of these proteins. At metaphase, CENP-E, Bub3 and Bub1 levels diminish by a factor of about three to four as compared with free kinetochores, whereas dynein/dynactin, Mad1, Mad2 and BubR1 levels are reduced by a factor of more than 10 to 100.
To achieve proper segregation, the two kinetochores on the sister chromatids must be attached to opposite spindle poles (bipolar orientation).

ZW10

ROD-ZW10 complex
The dynamic components that vary in concentration on kinetochores during mitosis include the molecular motors CENP-E and dynein (as well as their target components ZW10 and ROD), and the spindle checkpoint proteins (such as Mad1, Mad2, BubR1 and Cdc20). These proteins assemble on the kinetochore in high concentrations in the absence of microtubules; however, the higher the number of MTs anchored to the kinetochore, the lower the concentrations of these proteins. At metaphase, CENP-E, Bub3 and Bub1 levels diminish by a factor of about three to four as compared with free kinetochores, whereas dynein/dynactin, Mad1, Mad2 and BubR1 levels are reduced by a factor of more than 10 to 100.
The encoded protein binds to centromeres during the prophase, metaphase, and early anaphase cell division stages and to kinetochore microtubules during metaphase.

Aneuploidy

aneuploidaneuploidiesdisomy
If anchoring is incorrect, errors may ensue, generating aneuploidy, with catastrophic consequences for the cell.
Merotelic attachment occurs when one kinetochore is attached to both mitotic spindle poles.

BUB1B

BubR1MAD3
The dynamic components that vary in concentration on kinetochores during mitosis include the molecular motors CENP-E and dynein (as well as their target components ZW10 and ROD), and the spindle checkpoint proteins (such as Mad1, Mad2, BubR1 and Cdc20). These proteins assemble on the kinetochore in high concentrations in the absence of microtubules; however, the higher the number of MTs anchored to the kinetochore, the lower the concentrations of these proteins. At metaphase, CENP-E, Bub3 and Bub1 levels diminish by a factor of about three to four as compared with free kinetochores, whereas dynein/dynactin, Mad1, Mad2 and BubR1 levels are reduced by a factor of more than 10 to 100. At metaphase, CENP-E, Bub3 and Bub1 levels decreases 3 to 4 fold as compared to the levels at unattached kinetochores, whereas the levels of dynein/dynactin, Mad1, Mad2 and BubR1 decrease >10-100 fold.
The protein has been localized to the kinetochore and plays a role in the inhibition of the anaphase-promoting complex/cyclosome (APC/C), delaying the onset of anaphase and ensuring proper chromosome segregation.

BUB1

Mitotic checkpoint serine/threonine kinase
At metaphase, CENP-E, Bub3 and Bub1 levels decreases 3 to 4 fold as compared to the levels at unattached kinetochores, whereas the levels of dynein/dynactin, Mad1, Mad2 and BubR1 decrease >10-100 fold.
The protein is bound to kinetochores and plays a key role in the establishment of the mitotic spindle checkpoint and chromosome congression.

Ran (protein)

Ranran gtp-binding proteinRAN cycle
Whereas the spindle checkpoint protein levels present in the outer plate diminish as MTs anchor, other components such as EB1, APC and proteins in the Ran pathway (RanGap1 and RanBP2) associate to kinetochores only when MTs are anchored. This may belong to a mechanism in the kinetochore to recognize the microtubules' plus-end, ensuring their proper anchoring and regulating their dynamic behavior as they remain anchored.
RanBP2 (Nup358) and RanGAP move to the kinetochores where they facilitate the attachment of spindle fibers to chromosomes.

BUB3

At metaphase, CENP-E, Bub3 and Bub1 levels decreases 3 to 4 fold as compared to the levels at unattached kinetochores, whereas the levels of dynein/dynactin, Mad1, Mad2 and BubR1 decrease >10-100 fold.
As one of the checkpoint proteins, Bub3 delays the irreversible onset of anaphase through direction of kinetochore localization during prometaphase to achieve biorentation.

Cohesin

cohesin complexcohesion
Studies on Hec1 (highly expressed in cancer cells 1), the human homolog of Ndc80p, show that it is important for correct chromosome congression and mitotic progression, and that it interacts with components of the cohesin and condensin complexes.
Cohesin has been shown to be responsible for transcription regulation, DNA double strand break repair, chromosome condensation, pairing of homologous chromosomes during meiosis I, mono-orientation of sister kinetochores during meiosis I, non-homologous centromere coupling, chromosome architecture and rearrangement, DNA replication etc.

Mad1

The dynamic components that vary in concentration on kinetochores during mitosis include the molecular motors CENP-E and dynein (as well as their target components ZW10 and ROD), and the spindle checkpoint proteins (such as Mad1, Mad2, BubR1 and Cdc20). These proteins assemble on the kinetochore in high concentrations in the absence of microtubules; however, the higher the number of MTs anchored to the kinetochore, the lower the concentrations of these proteins. At metaphase, CENP-E, Bub3 and Bub1 levels diminish by a factor of about three to four as compared with free kinetochores, whereas dynein/dynactin, Mad1, Mad2 and BubR1 levels are reduced by a factor of more than 10 to 100. At metaphase, CENP-E, Bub3 and Bub1 levels decreases 3 to 4 fold as compared to the levels at unattached kinetochores, whereas the levels of dynein/dynactin, Mad1, Mad2 and BubR1 decrease >10-100 fold.
Mps1 phosphorylates Mad1 both in vitro and in vivo and is thought to regulate Mad1 and Mad2 localization to kinetochores and their interaction dynamics.

Telophase

nuclear division
Whereas structural centromeric proteins (such as CENP-B), remain stably localized throughout mitosis (including during telophase), the spindle checkpoint components are assembled on the kinetochore in high concentrations in the absence of microtubules, and their concentrations decrease as the number of microtubules attached to the kinetochore increases.
Spindle disassembly is an irreversible process which must effect not the ultimate degradation, but the reorganization of constituent microtubules; microtubules are detached from kinetochores and spindle pole bodies and return to their interphase states.

Protein

proteinsprotein synthesisproteinaceous
A kinetochore is a disc-shaped protein structure associated with duplicated chromatids in eukaryotic cells where the spindle fibers attach during cell division to pull sister chromatids apart.

Cell division

divisiondaughter cellcellular division
A kinetochore is a disc-shaped protein structure associated with duplicated chromatids in eukaryotic cells where the spindle fibers attach during cell division to pull sister chromatids apart.

Microtubule

microtubulesmicrotubularmicrotubule polymerization
The kinetochore assembles on the centromere and links the chromosome to microtubule polymers from the mitotic spindle during mitosis and meiosis.

Asia

AsianAsian continentAsian countries
In some areas in Asia however, the word is pronounced "connect-a-core", as it connects to the core of the chromosome.