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52 Cards in this Set
- Front
- Back
thymosin beta-4
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buffers microfilaments, keeps actin as a monomer by stabilizing actin-ADP
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profilin
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binds ADP-actin, displaces thymosin beta-4, exposes phosphate binding site so that actin-ADP --> actin ATP
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formin
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binds 2 profilin-actin-ATPs, adds to microfilament chains (SUMO wrestler)
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Arp 2/3
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actin branching protein - causes actin to branch if needed - used in lamellipodia
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cofillin
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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
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filamin
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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)
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dystrophin
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binds actin in the muscle to the sarcollemal membrane; without dystrophin - muscular dystrophy
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ezrin
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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
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villin, fimbrin, fascin
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forms tight cross-links between identically oriented actin filaments
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alpha-actinin
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forms looser cross-links between oppositely oriented actin filaments, leaves sufficient room for myosin II to intercalate (IN MUSCLE)
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Microfilaments
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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); |
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Microtubules
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polymeric tubes of alpha and beta-tubulin dimers, closely related subunits. INTRA-cellular transport, organelle placement, mitotic spindle; stabilize intermediate filaments
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Intermediate Filaments
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polymers of fibrous proteins, cell specific. structural integrity, cell-cell and cell-matrix bonding, nuclear stability; stabilized by microtubules
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stathmin
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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.
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kinesins
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on microtubules, moves towards the + end (towards plasma membrane), brings mitochondria and ER with it
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dyneins
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On microtubules, move towards (-) end of microtubule (towards centrosome), brings golgi with it. Also has a role in moving cilia and and flagella
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Lamins A, B, and C
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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
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vimentin
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type of IF - in mesenchymal cells
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desmin
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type of IF - in muscle
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type I (acidic) and type II (basic) keratins
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type of IF - in epithelium
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neurofilament proteins (NF-M, NF-L, NF-H)
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type of IF - in neurons
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desmosome
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"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
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hemidesmosome
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links epithelial cells to the basement membrane. It's a link to intermediate filaments inside the cell. Links to transmembrane proteins called integrins.
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cilia
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motile, inserted into basal bodies, type of microtubule, movement - relies on ATP
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microvilli
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important in absorption (small intestine), type of microfilament
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basal lamina/basement membrane
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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
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basal infoldings
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increases surface area on basal surface. way to stock mitochondria which increases their transport capabilities
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zonula occludens
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"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
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zonula adherens
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adheres two cells to eachother and to actin cytoskeleton; keeps cell upright; actin is involved in anchoring
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gap junctions
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involved cell-cell communication; made up of connexons
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cadherins
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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)
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Epidermolysis bullosa simplex
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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
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Charcot-Marie-Tooth disease
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mutations of IFs, abnormal neurofilaments (tangles), symptoms similar to amyotrophic lateral sclerosis (degeneration of motor nerves)
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vinculin
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actin binding protein in zonula adherens and focal contacts; binds actin filamens to adapter proteins (catenins)
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catenins
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adapter proteins in zonula adherens; binds actin-binding proteins (vinculin) to cadherins; subject to signalling system, can strengthen or weaker zonula adherens
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sphingosine-1-phosphate (S1P)
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helps modulate tightness of tight junctions (regulates permeability); asthma patients have higher permeability!
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occludens, claudens
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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
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desmogleins, desmocollins
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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
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desmoplakins, plakoglobins
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in desmosomes; adapter proteins; connects the intermediate filaments (keratins in epithelium) to the transmembrane proteins (desmogleins and desmocollins)
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desmoglein-1
desmoglein-3 |
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 |
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Emery-Dreyfus muscular dystrophy
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mutated lamin A or emerin. Limb-girdle muscular dystrophy, cardiomyopathy
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Charcot-Marie-Tooth disorder type 2B1
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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
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Pemphigus foliaceus
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build up autoantibodies to desmoglein -1; crusty sores, no oral problems
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Pemphigus vulgaris
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autoantibodies to desmoglein 3; blistering on body or oral cavity. involves intra-epithelial clefting
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bullous pemphigoid
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autoantibodies to demidesmosomal proteins BP180, BP230, laminin V, beta-4 integrin
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muscular dystrophies
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mutation of microfilament network; mutations of dystrophin, other proteins linking muscle microfilaments to the plasma membrane
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familial hypertrophic cardiomyopathy
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mutation of microfilament network;
mutations in beta-myosin heavy chain, seven other genes of myofibrillar apparatus |
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desmin-related myopathy
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type of IF mutation; causes chronic neuromuscular disroders
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dilated cardiomyopathy
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mutations in intermediate filaments;
mutated desmins; like other cardiomyopathies |
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integrins
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transmembrane protein that helps with extracellular binding; cell-specific; used in hemidesmosomes and focal contacts
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polycystic kidney disease, retinal degeneration
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defects in the kinesin complexes that carry cargo to the top of cilia/flagella
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plectin
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adapter proteins for hemidesmosomes; binds IFs to integrins in hemidesmosomes
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