Cytoskeleton/actin/if/microtubules

Front 1

Desmosomes

Back 1

special structures that anchor I.F, "buttons" and "rivets" and structural

Front 2

G Actin leads to ? what is the difference between the 2?

Back 2

F Actin, G actin is monomers of actin, bind ATP to become dimers, trimers, then F-Actin triple helix

Front 3

Branching elements of F-actin microfilaments is done by what complex?

Back 3

Arp2/3 complex-faciliates cut/nucleation in other directions

Front 4

Microfilament bundles are formed by ? of F-actin by ?.

give 2 examples

Back 4

crosslinking-stabilized actin bundle=close crossling due to short segment

ex) microvilli crosslinked by Fimbrin and Villin
ex) stress fibers cross linked by alpha-Actinin

Front 5

Microfilament networks are made via _____ of F-actin by what? give 2 examples.

Back 5

crosslinking of F-actin by Filamin

ex) pseudopodia for phagocytosis
ex) lamellipodia in leading edge during cell movement

Front 6

Myosin types

Back 6

I,II,V, VI

II=sarcomeric, smooth muscle,non muscle myosins

Front 7

Describe treadmilling.

____ is added to the plus end and removed from the minus end.

Back 7

G-actinxATP added to plus ends of F-actin at a much faster rate than minus ends bc ADP-actin dissociates more readily than ATP-actin

treadmilling results from diff in concentration of G-actin=balance

Front 8

myosin ______ along microfilaments

Back 8

"walks"

Front 9

parts of myosin heavy chains

parts of myson light chains

Back 9

heavy=motor (head) ATPase activity, neck (lever) binds MLC/calmodulin, tail (rod) variable in length/sequence

light=bind to MHCs/regulate myosin func.

Front 10

Type II myosin used in what types of junctions/filaments

Back 10

microfilaments used in stress fibers in focal adhesions, adherens junctions, contractile rings

Hint 10

Yo man, I got some rings, a got some local ads, and I got some junk. but I only got 2 of each....

rings, focal adhesions, adherens, junctions=TYPE II

Front 11

what complex turns on/activates the motor protein of myosin? what does this cause?

Back 11

Ca/Calmodulin/Mysonin Light Chain Kinase. causes/helps rod filaments assemble and slide the filaments together=contraction

Front 12

Myosin I has important function in ______ where it forms "struts" btw microfilaments and cell membrane

Back 12

microvilli

Front 13

myosin I moves along microfilament toward the ___ end. carrying cargo linked to the ___domain.

Back 13

+ end, carries cargo on the tail domain

is made up of 1 MHC, MLCs and Calmodulin

I am POSITIVE it's my ONLY (1) sin (Myosin 1)

Front 14

Myosin V consists of ____

motor domains walk towards the ___ end

Back 14

2 MHCs, MLCs, and Calmodulin

+ end

V, w, X yz X=+

Front 15

myosin VI walks toward the ___ end

Back 15

minus end

Front 16

cell motility happens when _____ attaches to the substratum, which develops ____ and thus, forward movement

Back 16

lamellipodium attaches to the substratum, which develops tension

Front 17

cell motility: cell moves forward due to the rapid ______ of ______ at the ____end which is faster than the ___ end

Back 17

polymerization of F-actin at the plus end is faster than the minus end.

Front 18

desminopathies are what?

Back 18

cardiac and skeletal myopathies caused by mutations in desmin gene

Front 19

desmin is the key ________ protein of cytoskeleton in ____ and ___ muscles that maintains structural integrity of _______ apparatus

Back 19

intermediate filament protein in the cytoskeleton in cardiac and skeletal muscles that maintains structural integrity of the contractile apparatues

Front 20

microtubules are make up of ____ and ____ that form a______.

Back 20

alpha and beta tubulin that for a heterodimer

Front 21

alpha tubulin has bound_____ that ______hydrolyze

beta tubulin has bound _____ that ____hydrolyze

Back 21

GTP that does NOT hydrolyze

Beta has GTP that DOES hydrolyze into GDP and Pi

Front 22

alpha and beta tubulin heterodimers form a _________

Back 22

hollow cylinder with 13 protofilaments

Front 23

blistering comes from

Back 23

mutations in intermediate filaments that help connect the epidermis to the dermis

epidermolysis bullosa simplex

Front 24

pathologists can track where cancers came from via the

Back 24

types of intermediate filaments they started from. have certain antibodies on them now

Front 25

microtubule-associated proteins (MAPs) regulate

6 things they regulate

Back 25

regulate behavior of MTs-bind directly to MTs or Tubulin dimers

1) assembly-polymerization rate
2)stabilization-capping
3)cross-linking-spacing/linking
4)tracking-directing to targets
5)destabilization-preventing assembly
6)severing-capping ends to stop polymerization

Front 26

Kinesins carry cargo toward ____ toward the ___ end

Dyneins carry cargo _______toward the ____ end

Back 26

outward toward the plus end


dyneins carry cargo inward toward the minus end

globular heads have ATPase and walk along MT

tail domains have sequence specific binding proteins to bind to cargo

Front 27

cilia vs. flagella

Back 27

cilia line epithelial cells to help move fluid/particles

flagella-propel sperm

Front 28

axoneme is composed of _____ in a 9+2 array

structural proteins=
movement proteins=

Back 28

MTs

nexin
dynein

Front 29

molecular basis for movement

Back 29

dynein affixed to A tubules
motor heads of dynein move along B tubules toward minus end

because connected by nexins, forces generate by dynein heads cause MTs to bend

Front 30

MTs used in chemo because?

Back 30

disrupt assembly of mitotic spindles during Mitosis and block M phase of cell cycle

Front 31

alzheimers and MTs

Back 31

neurofibrillary tangles=abnormal hyper-phosphorylated filaments of MTs associated with Tau (MT protein that stabilizes poly/inhibits depoly)

these tangles correlate with alzheimer's. role unknown.

Front 32

Intermediate Filaments are ___ structures with ___ and __ end. Maintain cell structure...

There are 4 types

Back 32

Filling entire volume of cell, cradles nucleus (positions it)

Keratin, Vimentins, Nuclear lamina, Neurofilaments

Front 33

Keratin

Characteristics

Back 33

Type of IF

Contains heterodimers of acidic and basic keratins

There are multiple keratin isoforms / specific Keratin for specific epithelium

Associated with Desmosomes for cell to cell contact

- Helps deal with shear/stretch stress, allows cells to be stretched w/o lysing

Front 34

Keratin Disorders

Back 34

Epidermolysis bullosa simplex

- inherited skin blistering disease from mutations in basal cell (K5/14) keratins, patients are very sensitive to physical stress.

- null mutation (no keratin) -> great mechanical stress can cause cell lysis

- Auto/dom. mutation: (weird keratin) -> minor stress causes cell lysis

Front 35

Vimentins

Characteristics

Back 35

Found in mesenchymal cells (origination of osteoblast, chrondocytes, myosytes, adipocytes), blood vessel endothelium, and some epithelia

- Terminate at nuclear membrane and cell surface desmosome, Hold nucleus at permanent location

- associate with MT's via accessory proteins

- maintain cell organization

- become reorganized during mitosis.

Front 36

Neurofilaments

Back 36

heteropolymer, fills core of neuronal axons

Associate with axonal MT's

control radial growth of neural axons

- # filaments = speed of conduction.

"Quiver" mutant in quail blocks NF formation & speed of conduction.

Front 37

Nuclear Lamina

Back 37

attached to inner surface of nuclear membrane via a lamin B receptor and is remodeled during mitosis.

There are 3 lamins (A,B, and C)

- Phophorylation of all 3 is required for depolymerization.

Front 38

MTs

Back 38

consist of alpha/beta units

GTP bound to Alpha is buried and cannot be used (just needed)

-GTP bound to beta is accesible and hydrolyzes

- C-terminus is very acidic and used to bind to a variety of accessory proteins.