Cytoskeleton
Terms
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- G-Actin
- monomer of microfilaments
- F-Actin
- helical polymer fo microfilaments
- lag phase of actin polymerization
- formation of actin trimer (nucleation site)
- Actin-binding proteins
- versatile family of proteins that crosslink actin filaments into loose gells, bind them into stiff bundles, attach to PM, or move them
- minimyosin (myosin 1)
- motor protein of actin filaments in non-muscle cells
- filamin
- protein that crosslinks actin filaments into gel
- spectrin
- protein that crosslinks filaments to PM by their sides
- fimbrin
- protein that bundles actin filaments
- α actinin
- protein that bundles actin filaments and links actin filament to viniculin at focal contacts
- gel solin
- calcium dependent protein that severs or fragments actin filaments
- cap-Z
- protein that caps the positive end of actin
- profilin
- protein that binds actin monomers and inhibits polymerization
- Cytochalasins
- drug that blocks cell movement by binding to + end of actin to block polymerization and inhibit motility, phagocytosis, organelle and vesicle trafficking and production of lamellipodia and filopodia
- Focal contacts
- place that actin attaches the cell PM to extracellular matrix
- Integrins
- family of transmembrane proteins that link ECM's fibronectin w/ cytoplasmic actin filaments of stress fibers with attachment proteins
- talin
- protein that links viniculin to integrin at focal contacts
- viniculin
- protein that links α actinin to talin at focal contacts
- integrins linkage at focal contacts
- transmembrane protein that links talin to fibronectin
- ankyrin
- protein mainly responsible for attaching the spectrin cytoskeleton to red cell PM
- filopodia
- thin stiff protrusions of the cell surface that form and reform quickly and contain a bundle of actin filaments
- lamellipodia
- thin sheetlike processes of cell surface made of actin filament involved in cell movement
- tubulin
- dimer of α and β tubulin. The subunit of microtubules
- protofilaments
- long parallel rows into which tubulin molecules align; 13 make a microtubule
- kinesins
- motor protein family that move along microtubules. Associated with ER
- dyneins
- motor protein family that move toward the α end of microtubules. Ciliary and cytoplasmic varietys exist and are associated with the golgi
- colchicine
- antimitotic drug which binds to free tubulin and prevents polymerization
- taxol
- antimitotic drug which binds to microtubules and prevents depolymerization
- γ-tubulin
- ring shaped structure of centrosome which acts as the nucleation-site of a microtubule
- dynamic instability
- property of microtubules based on rapid polymerization and depolymerization (if GTP of plus end is hydrolyzed before the next tubulin is added)
- centrioles
- pair of cylindrical microtubule structures in the centrosome
- arrangement of microtubules in centrioles
- 9 + 0
- arrangement of microtubules in cilia
- 9 + 2
- basal bodies
- accumulation of centrioles beneath the PM which initiate tubulin polymerization to form the axoneme of cilia or flagella
- arrangement of microtubules in basal bodies
- 9 + 0
- axoneme
- core of each cilium with 9 microtubule doublets around a pair of unjoined mt's
- ciliary dynein
- protein that forms the arms that extend from subfiber A and hydrolyze ATP to generate a sliding force that moves cilia
- nexin
- protein that forms bridges to link adjacent doublets in axonemes
- radial spokes
- link the doublets to the sheath in axonemes
- sheath
- surrounds the central microtubule pair of axonemes
- effective stroke
- stiff rapid forward stroke of cilia
- recovery stroke
- slower bending stroke of cilia
- keratins
- cytoplasmic IF in epithelial cells and their derivatives
- vimentin
- IF in cytoplasm of cells of mesenchymal origin
- neurofilaments
- IF in cytoplasm of neurons
- lamins
- IF in nucleus
- filaggrin
- protein in epidermis of skin that bundles keratin IF into tonofilaments
- tonofilaments
- bundles of keratin IF
- What are the 3 types of proteins assemblies in the cytoskeleton
- microfilaments, microtubules and intermediate filament
- Where is the highest concentration of microfilaments
- cortex (just beneath PM)
- What does nucleotide hydrolysis promote in F-Actin?
- depolymerization
- What are the three phases of polymerization of actin?
- 1) Lag phase 2) Growth (polymerization) 3) steady state (treadmilling)
- What are the 3 forms of association that actin bundles can have?
- contractile, gel-like networks and parallel bundles
- What is the function of microfilaments in the cell cortex?
- mechanical strength, cell shape and locomotion
- What is dispatched in response to an antibody binding to its receptor?
- IP3
- Cell migration requirements
- actin, microtubules, intermediate filaments and PM
- What stimulates calcium release from storage vesicles into the cytosol during the gelsol state of the cortical cytoplasm?
- IP3
- What two proteins are used to for the gelsol state during psuedopod formation?
- GELSOLIN fragments the actin filaments, and PROFILIN inhibits repolymerization
- How does a cell travel across a surface?
- CELL CRAWLING: 1) Protrusion of leading edge 2) attachment btwn leading edge and surface 3) traction-attached edge pulls cell forward
- What are the two types of directional motors for locomotion?
- Actin based and microtubule based
- How does microtubule based locomotion work?
- active transport of membrane vesicles to the leading edge
- What is required for microtubule polymerization
- GTP and Mg++
- what labile microtubules are stabilized by
- attaching to another molecule or cell structure
- examples of stable microtubules
- centrioles, basal bodies, cilia, and flagella
- functions of cilia
- movement of mucus along conducting airways of respiratory system, transportation of oocytes, movement of sperm through efferent ducts
- rhythm of Cilia
- metachromal
- the toughest and most durable cytoskeletal filament
- intermediate filament
- main function of intermediate filament
- withstand mechanical stress when cells stretched
- where can intermediate filaments be found
- cell-cell junctions, nucleus
- which form of protein assemblies don't require energy
- intermediate filament
- which cytoskeletal proteins have polarity
- microfilaments, and microtubules