Kinesin And Dynein

Front 1

What are the four types of motors? What do their heads bind to? What do the tails bind to? What are the directions of head motion towards?

Back 1

Myosin I: Tail binds to cell membrane, head binds to actin, direction: +
Myosin II: Tail binds to myosin II, head binds to actin, toward: +
Kinesin: Tail binds to vesicle, Head binds to microtubules, toward +
Cytoplasmic dynein: Tail binds to vesicle, head binds to microtubules, toward -

Front 2

Which way does kinesin walk toward? Dynein?

Back 2

Kinesin: towards + end (toward peripherial)
Dynein: towards - end

Front 3

The motors undergo conformation changes during:

Back 3

hydrolysis of ATP

Front 4

Dynein complex for vesicle transport: what is the motor, what is the complex involved in doing? What does it act as?

Back 4

Dynein is the motor, the complex is involved with holding the dynein in place and also acts as a 'shock absorber as the vesicle moves through the cytoplasm

Front 5

Where is the plus end of microtubules?
How does kinesin work in this? Dynein? What are these transports called?

Back 5

Plus is in the Periphery of the cell. (in axons, this can be meters in length)
Kinesin will carry cargo to the periphery. Dynein carries cargo from the periphery to the cell body

Anterograde is associated with kinesin, retrograde is associated with cytoplasmic dynein

Front 6

What is retrograde transport? Anterograde transport?

Back 6

Anterograde: kinesin to the plus end (synapse, away from cell body)
Retrograde: dynein to the negative end (towards cell body)

Front 7

Can filaments move over motors?

Back 7

Yes--myosin heads were immobilized onto a glass side, and actin filaments were moved over the top::called'gliding'
Take home point: microfilament or microtubule can also be moved in the cell, so kinesin or dynein can travel over the MT

Front 8

Cells attach to their environment via

Back 8

Focal adhesions (integrins with alpha and beta subunits...lots of stuff involved in the complex)

Front 9

How are integrins different from other cell adhesion proteins? What are the 2 characteristics of beta subunits?

Back 9

They consist of 2 subunits (alpha and beta)

They have a dual function: they bind to both the ECM and the internal skeleton

The beta subunit has 2 characteristics: the extracellular chain contains repeating cystein rich regions, and the intracellular portion interacts with actin filaments via 3 connecting proteins (talin, vinculin, alpha actinin)

Front 10

How are microtubules related to focal adhesions?

Back 10

Microtubules extend, and at the end there is a terminal complex "X" move towards FA and signal and disrupt the FA., yet they also take place in forming FA (carrying cargo)

It's a path of polymerization, touching FA, depolymerize and move away

So you either get a FA, or you lose an FA

Front 11

Ameboid movement: what is associated with actin based cell migration?

Back 11

lamellapodia (actin polymerization)

Front 12

How does the cell move by actin polymerization? Concentrated actin at the leading edge is controlled by what complex?

Back 12

Cell makes attachments to the substrate via FA. Actin then polymerizes at the growing edge of the cell (lamellapodia) The back has a loss of focal adhesions.

Actin filaments forming will push membrane out and actin polymerization leads to new FA created, a denser network is formed that pushes the membrane out more and then another FA is created, etc.

ARP complex controls the concentration of actin at the leading edge

Front 13

Actin is concentrated at the edge. What is present as a little further from this layer? What is its purpose?

Back 13

Actin and cofilin. Actin binds with cofilin, which makes the helix tighter (controls actinpolymerization, in a way)

Front 14

Stress fibers are also known as

Back 14

filapodia

Front 15

Movement of microtubules is due to the:

Back 15

movement of the entire MT by "gliding", and also by the depolymerization of the plus end of the MT in the periphery

Front 16

MT will sometimes run atop the FA; however, FA are directly linked to what?

Back 16

Actin skeleton

Front 17

MT and FA....

Back 17

MT extend to FA, but this signals the destabilization of the MT, conversely the MT also causes disruption of the FA

Front 18

When stress is applied, focal adhesions...

Back 18

increase in size, more FA are made, cells will resist the mechanical stress i.e. skin

size of FA change base on local stimuli within the microenvironment of the cell

MT is involved with that because MT will be signaling the disruption of FA

Front 19

What is the basic structure of cilia and flagella? What is the arrangement? What motor protein extends between the arms to form a ring around the outside arrangement?

Back 19

Axoneme 9+2 microtubules.
Dynein extends between MTs to form a ring around the outer rings

Front 20

When dynein is active it causes a shear force in the MTs of the axoneme, what does this cause?

Back 20

the activation travels up and down the cilia or flagella to create a circular motion in the structure

Front 21

In normal flagellum of cilia and flagella, dynein causes MTs to

Back 21

Bend (shear) i.e. sperm works as a rotary motor, working like a propeller

Front 22

In the beat pattern of cilia, which way does the mucus move?

Back 22

Left to right (kinda like a clockwise rotation) positions 1-9 mucus is not in contact::moves cilia under th emucus position 10 the cilia is in contact with mucus, and positions 11 and 12 the cilia pushes the mucus to the right

Front 23

How can you increase cilia beating pattern?

Back 23

Movie of tapping cell::CALCIUM rushes in and affects how cilia beat, but it also affects surrounding cells and ALL increase. Spreads through gap junctions

Front 24

Beating of the cilia is controlled by

Back 24

Intracellular calcium

Front 25

Does smooth muscle have striations? What does it have a lot of? What is used to produce a contraction?

Back 25

No striations: has a lot of actin and myosin, as well as gap junctions (calcium is a big signaling molecule)

Actin and myosin produces contraction

Front 26

What are dense bodies?

Back 26

cytoplasmic places where plus ends of the actin filaments will attach:: protein plaque where the actin will attach and the minus ends are spread out


Little black dots in the cell

Front 27

What is the shape of the nucleus in the smooth muscle? What surrounds each smooth muscle to help attach to ECM and neighboring cells?

Back 27

Nucleus is in the middle, is spindle shaped

Basal lamina will surround them

Front 28

Where can you find lots of smooth tissue? What can you say about the cell?

Back 28

In the GUT (no striations) Lots of nucleus, very little cytoplasm

Smooth muscles also surround blood vessels, and how they are structure will help determine if it's an artery or vein

Lots of dense bodies in the cell as well.

Front 29

Smooth muscle contraction. What happens? What controls it? How is calcium involved?

Back 29

Calcium binds to calmodulin, this complex will then bind to and activate the MYOSIN LIGHT CHAIN KINASE.

this kinase is then phosphorylated and becomes the MYOSIN LIGHT CHAIN, and the tail EXTENDS and is able to interact with ACTIN for contraction (phosphorylated myosin forms a think filament by binding the tail of other myosins, and then they interact and "walk" along an actin filament)

Phosphatases will remove phosphate from myosin, causing the tail to curl

Front 30

When contracted, what is the orientation of the smooth muscle (including dense bodies)?

Back 30

Tail to tail orientation complex is formed, moving dense bodies close together, creating a great meshwork

BASICALLY: Myosin filaments form, and pull the actin filaments, moving dense bodies together

Front 31

What are the two main players in contraction of smooth muscle?

Back 31

KINASES AND PHOSPHATASES
kinases straighten the tail, phosphatases curl it up

Front 32

http://www.ncbi.nlm.nih.gov/books/NBK22572/

Back 32

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