C-17-C Mitosis

rearrangements

In animal cells, M-Cdk promotes the ___ of the actin cytoskeleton and the Golgi apparatus

nuclear envelope

In animal cells, M-Cdk promotes the breakdown of the ___ ___

Polo-like and Aurora kinases

M-Cdk doesn't work alone; two additional families of protein kinases that contribute to control of early mitotic events

sister chromatid

M-Cdk must ensure that each ___ ___ is attached to the opposite pole of the spindle

assembly

M-Cdk must induce the ___ of the mitotic spindle

disassembly

M-Cdk phosphorylation of pore complexed initiates its ___ and their dissociation from the envelope

chromosome condensation

M-Cdk triggers it; the large-scale reorganization of the intertwined chomatids into compact, rod-like structures

tubulin subunits

Ndc80 links the microtubules to kinetochore but still allows for addition and removal of ___ ___

negative

___ checkpoint signal in spindle assembly checkpoint mechanism depends on several proteins, including Mad2

mitotic spindle

a bipolar array of microtubules, which pulls sister chromatids apart in anaphase

kinetochore

a giant, multilayered protein structure that is built at the centromeric region of the chromatid; attaches sister chromatids to spindle

centriole

a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.

Polo-like kinase or Plk

a protein kinase required for the normal assembly of bipolar mitotic spindle; it phosphorylates proteins involved in separation of the spindle poles

Aurora-A kinase

a protein kinase that also helps control proteins that govern the assembly and stability of the spindle

Aurora-B kinase

a protein kinase that controls the attachment of sister chromatids to the spindle

M-Cdk activity

activation of Polo-like and Aurora kinases are dependent on ___ ___

absence of centrosomes

another attachment mechanism that also plays a part

nuclear lamina

another component phosphorylated by M-Cdk; the structural framework beneath the envelope

Cdc20-APC/C activation

any kinetochore that is not properly attached to the spindle sends out a diffusable negative signal that blocks ___ ___ throughout the cell

opposite sides

at end of prophase in animal cells, centrosoms of growing spindle can be found on ___ ___ of nuclear envelope

prometaphase

breakdown of nuclear envelope, chromosomes begin to attach to spindle microtubules via their kinetochores and undergo active movement

microtubule-dependent motor proteins

cells that do not have centrosomes used these and other proteins to asociate microtubule minus ends to organize and focus the spindle poles

metaphase

chromosomes aligned in equator of spindle, kinetochore microtubules attach sister chromatids to opposite poles

cytokinesis

cytoplasm divided in two by contractile ring of actin and myosin filaments, which pinches the cell in 2, makes cleavage furrow

M-Cdk

drives entry into mitosis

colchicine or vinblastine

drugs that destabilize microtubules that arrest cells in mitosis for hours to days

pericentriolar matrix

each centrosome consists of a cloud of amorphous material called the ___ ___ that surrounds a pair of centrioles

senses tension

how a sensor mechanism in spindle assembly checkpoint works

1

how many microtubules bind to a kinetochore of a budding yeast cell

10-40

how many microtubules bind to a kinetochore of an animal cell

timing

in mammalian somatic cells, spindle addembly chekpoint determines the normal ___ of anaphase

coiled-coil proteins

in matrix; a microtubule-dependent motor protein that links motors to centrosome, structural proteins and components of cell cycle control system

y-tubulin ring

in matrix; component mainly responsible for nucleating microtubules

emdedded head-on

in metaphase, kinetochore microtubules are ___ ___ in special attachment sites

centrosome

in most somatic animal cells, an organelle near the nucleus of a cell that contains the centrioles and from which the spindle fibers develop in cell division.

unstable lateral attachments

initial attachments of microtubules to kinetochore; kinetochore attaches to side of passing microtubule with help from kinesin motor proteins

kinetochores

located at the centromere of each sister chromatid

spindle assembly checkpoint mechanism

mechanism that ensures cells do not enter anaphase until all chromosomes are correctly bi-oriented on the mitotic spindle

minus ends

microtubule ends that are focused at the two spindle poles

plus ends

microtubule ends that radiate outward from the poles

nuclear pore complexes

nuclear envelope breakdown is thought to begin when M-Cdk phosphorylates several subunits of the ___ ___ ___ in the nuclear envelops

nucleates

pericentriolar matrix ___ a radial array of icrotubules with their fast-growing plus ends projecting outward and their minus ends associated with the centrosome

kinetochore microtubules

plus ends of microtubules that are attached to sister-chromatid pairs at large protein structures called kinetochores

interpolar microtubules

plus ends of microtubules that overlap with plus ends of microtubules from other pole, resulting in an antiparallel array in spindle mid-zone

astral microtubules

plus ends of microtubules that radiate outward from the poles and contact the cell cortex, helping to position the spindle in the cell

Mad2

protein recruited to unattached kinetochores that act like enzymes and catalyzed conformation change in this protein to bind/inhibit Cdc20-APC/C

control of chromosome movement

regulation of plus-end polymerization and depolymerization at the kinetochore is critical for?

prophase

replicated chromosomes condense, mitotic spindle assembles , two centrosomes replicate and move apart; beginning of mitosis

Ndc80

rod-shaped protein complex that determines the attachment of each microtubule; anchroed in kinetochore at one end and interacts with sides of microtubule at the other

anaphase

sister chromatids synchronously separate toward spindle pole, kinetochore microtubules get shorter, spindle poles move apart

orientation

soon, dynamic microtubule plus ends capture the kinetochores in the correct end-on ___

sensor mechanism

spindle assembly checkpoint depends on this to monitor strength of microtubule attachment to kinetochore

chromosome segregation

the central event of mitosis

nuclear envelope breakdown

the completion of spindle assembly in animal cells require ___ ___ ___; a complex multistep process

short microtubules

these microtubules in vicinity of chromosomes become embedded in plus-end binding site of kinetochore, polymerize and grow away from it, cross-link to other minus ends, and focused by motor proteins at pole

metaphase-to-anaphase transition

transition stage whose progression is blocked by the spindle assembly checkpoint mechanism

telophase

two sets of daughter chromosomes arrive at poles and decondense, new nuclear envelope reassembles around each set, end of mitosis. contractile ring start to contract

phosphorylation

what does M-Cdk do to specific proteins to trigger various processes

small vesicles

what happens when envelope breaks down? envelope breaks down into

bombarded

when envelope breaks down, sister chromatid pairs are ___ by microtubule plus ends coming from two directions

removed

when last sister-chromatid pair is properly bi-oriented, the block is ___

cytoplasm

where centrosomes and microtubules of animal cells are located

nucleus

where many motor proteins and microtubule regulators that promote spindle assembly are located