Microfilament Proteins

Front 1

thymosin beta-4

Back 1

buffers microfilaments, keeps actin as a monomer by stabilizing actin-ADP

Front 2

profilin

Back 2

binds ADP-actin, displaces thymosin beta-4, exposes phosphate binding site so that actin-ADP --> actin ATP

Front 3

formin

Back 3

binds 2 profilin-actin-ATPs, adds to microfilament chains (SUMO wrestler)

Front 4

Arp 2/3

Back 4

actin branching protein - causes actin to branch if needed - used in lamellipodia

Front 5

cofillin

Back 5

cleaves and then releases actin-ADP from the microfilament; also releases Arp 2/3 and recycles it so it can be used again to create more branches

Front 6

filamin

Back 6

microfilament cross-linking protein that makes orthogonal connections to microfilaments - creates NETWORKS; also, binds to specific membrane proteins in the plasma membrane (Ex: binds integrins that fxn as adhesions between cells and matrix)

Front 7

dystrophin

Back 7

binds actin in the muscle to the sarcollemal membrane; without dystrophin - muscular dystrophy

Front 8

ezrin

Back 8

signal regulated - in active state, binds integral membrane protein and actin. In inactive state, two binding sites on ezrin bind eachother; MEANS by which the actin cytoskeleton can be recruited to a special site on the membrane

Front 9

villin, fimbrin, fascin

Back 9

forms tight cross-links between identically oriented actin filaments

Front 10

alpha-actinin

Back 10

forms looser cross-links between oppositely oriented actin filaments, leaves sufficient room for myosin II to intercalate (IN MUSCLE)

Front 11

Microfilaments

Back 11

Polymers of actin, a globular protein.
Cell Shape (platelets - helps to clot blood), Adhesion (anchors cell-cell adhesion complexes - zonula occludens and zonula adherens - and cell-matrix adhesion complexes), Contraction, Motility,
(pneumonic: Sumos Are Cool Males);

Front 12

Microtubules

Back 12

polymeric tubes of alpha and beta-tubulin dimers, closely related subunits. INTRA-cellular transport, organelle placement, mitotic spindle; stabilize intermediate filaments

Front 13

Intermediate Filaments

Back 13

polymers of fibrous proteins, cell specific. structural integrity, cell-cell and cell-matrix bonding, nuclear stability; stabilized by microtubules

Front 14

stathmin

Back 14

regulates tubulin formation. when phosphorylated, it doesn't bind tubulin and tubulin is allowed to polymerize. When not phosphorylated, it binds tubulin and polymerization is not allowed.

Front 15

kinesins

Back 15

on microtubules, moves towards the + end (towards plasma membrane), brings mitochondria and ER with it

Front 16

dyneins

Back 16

On microtubules, move towards (-) end of microtubule (towards centrosome), brings golgi with it. Also has a role in moving cilia and and flagella

Front 17

Lamins A, B, and C

Back 17

type of intermediate filament - in the inner lining of the nuclear membrane; change stability if necessary for meiosis/mitosis. When undergoing division, phosphorylized, become more labile

Front 18

vimentin

Back 18

type of IF - in mesenchymal cells

Front 19

desmin

Back 19

type of IF - in muscle

Front 20

type I (acidic) and type II (basic) keratins

Back 20

type of IF - in epithelium

Front 21

neurofilament proteins (NF-M, NF-L, NF-H)

Back 21

type of IF - in neurons

Front 22

desmosome

Back 22

"spot weld" - keeps material from flowing between 2 cells; held to cell by a type of IF called keratin; also, cadherins (type of protein) are involved; provides tensile strength and protects epithelium from tearing

Front 23

hemidesmosome

Back 23

links epithelial cells to the basement membrane. It's a link to intermediate filaments inside the cell. Links to transmembrane proteins called integrins.

Front 24

cilia

Back 24

motile, inserted into basal bodies, type of microtubule, movement - relies on ATP

Front 25

microvilli

Back 25

important in absorption (small intestine), type of microfilament

Front 26

basal lamina/basement membrane

Back 26

provides structural support, acts as a filter, establishes polarity, controls epithelial growth and differentiation - without it, cells would go in the wrong place and face the wrong way. Basal lamina is made by epithelial cells. Basement membrane has 1 xtra layer from fiberglass

Front 27

basal infoldings

Back 27

increases surface area on basal surface. way to stock mitochondria which increases their transport capabilities

Front 28

zonula occludens

Back 28

"tight junction" - keeps things out of the cell; tightness is based on the amount of "sealing strands," connections between actin filament systems of neighboring cells

Front 29

zonula adherens

Back 29

adheres two cells to eachother and to actin cytoskeleton; keeps cell upright; actin is involved in anchoring

Front 30

gap junctions

Back 30

involved cell-cell communication; made up of connexons

Front 31

cadherins

Back 31

STRONGEST intercellular transmembrane binding proteins! responsible for organizing and maintaining epithelial junctions that depend on Ca2+ - found in desmosome, zonula adherens; when cadherins for desmosome are destroyed due to autoantibodies (pemphigus), desmosomes in lateral domain destroyed (hemidesmosomes are ok)

Front 32

Epidermolysis bullosa simplex

Back 32

mutation of the intermediate filaments; defective keratins 5 and 14 in basal skin layer due to mutation; severe blistering disease; more serious than other keratin mutations, because it affects the basal layer of cells. early onset

Front 33

Charcot-Marie-Tooth disease

Back 33

mutations of IFs, abnormal neurofilaments (tangles), symptoms similar to amyotrophic lateral sclerosis (degeneration of motor nerves)

Front 34

vinculin

Back 34

actin binding protein in zonula adherens and focal contacts; binds actin filamens to adapter proteins (catenins)

Front 35

catenins

Back 35

adapter proteins in zonula adherens; binds actin-binding proteins (vinculin) to cadherins; subject to signalling system, can strengthen or weaker zonula adherens

Front 36

sphingosine-1-phosphate (S1P)

Back 36

helps modulate tightness of tight junctions (regulates permeability); asthma patients have higher permeability!

Front 37

occludens, claudens

Back 37

transmembrane proteins in tight junctions, forms barrier and helps regulate the permeability; microfilaments bind adapter proteins (ZO-1, 2, and 3) which then bind the occludens/claudins

Front 38

desmogleins, desmocollins

Back 38

in desmosomes, are transmembrane, homophilic adhesion proteins of the cadheren family. intermediate filaments bind the adapter proteins (desmoplakins, plakoglobins) which then bind the desmogleins and desmocollins

Front 39

desmoplakins, plakoglobins

Back 39

in desmosomes; adapter proteins; connects the intermediate filaments (keratins in epithelium) to the transmembrane proteins (desmogleins and desmocollins)

Front 40

desmoglein-1
desmoglein-3

Back 40

desmogleins in general are the transmembrane proteins (in cadherin family) for the desmosomes

1 - present in all layers of the epidermis, if there's an auto-immune reaction to, will often cause pemphigus folliaceus - won't effect basal lamina
3 - present in basal and spinous layers - if atuo-immune reaction to, may not have ill effects because 1 will make up for it

Front 41

Emery-Dreyfus muscular dystrophy

Back 41

mutated lamin A or emerin. Limb-girdle muscular dystrophy, cardiomyopathy

Front 42

Charcot-Marie-Tooth disorder type 2B1

Back 42

type of laminopathy (mutations of lamins or lamin-binding proteins) progressive peripheral neuropathy similar to that caused by diabetes. Later in life than type 1. Caused by lamin A mutation

Front 43

Pemphigus foliaceus

Back 43

build up autoantibodies to desmoglein -1; crusty sores, no oral problems

Front 44

Pemphigus vulgaris

Back 44

autoantibodies to desmoglein 3; blistering on body or oral cavity. involves intra-epithelial clefting

Front 45

bullous pemphigoid

Back 45

autoantibodies to demidesmosomal proteins BP180, BP230, laminin V, beta-4 integrin

Front 46

muscular dystrophies

Back 46

mutation of microfilament network; mutations of dystrophin, other proteins linking muscle microfilaments to the plasma membrane

Front 47

familial hypertrophic cardiomyopathy

Back 47

mutation of microfilament network;
mutations in beta-myosin heavy chain, seven other genes of myofibrillar apparatus

Front 48

desmin-related myopathy

Back 48

type of IF mutation; causes chronic neuromuscular disroders

Front 49

dilated cardiomyopathy

Back 49

mutations in intermediate filaments;
mutated desmins; like other cardiomyopathies

Front 50

integrins

Back 50

transmembrane protein that helps with extracellular binding; cell-specific; used in hemidesmosomes and focal contacts

Front 51

polycystic kidney disease, retinal degeneration

Back 51

defects in the kinesin complexes that carry cargo to the top of cilia/flagella

Front 52

plectin

Back 52

adapter proteins for hemidesmosomes; binds IFs to integrins in hemidesmosomes