Title: Webstraw: Cell Bio Anki Deck / Section 9 - Cytoskeleton: Intermediate Filaments

characteristics of intermediate filaments
1. not globular
2. no ATP/GTP needed
3. no polarity
4. no motor proteins
5. less dynamic

Q: [...] is the basic subunit of intermediate filaments
A: tetramer

types of intermediate filaments
1. keratin - tissue strength
2. desmin - provides strength to muscle
3. vimentin - sacromere organization
4. neurofilament - axon organization
5. lamin - nuclear organization

Q: lamins support nuclear membrane via [...] linking using [...] complex
A: prenylation; LINC

Q: intermediate filaments disassemble during [...]
A: mitosis

Q: [...] links intermediate filaments and microtubules
A: plectin

Q: general function of intermediate filaments are for [...]
A: structural support

Q: [...] links epithelial cells to each other and the dermis
A: keratin

Q: transgenic mice with mutated [...] had weak skin integrity
A: keratin

Q: intermediate filaments are anchored to [...] and [...]
A: desmosomes; hemidesmosomes

Q: [...] links adjacent epithlial cells
A: desmosomes

Q: [...] links epithlial membrane to extracellular matrix
A: hemidesmosomes

Q: [...] are channels between adjacent epithlial cells used for [...]
A: gap junctions; communication

Q: [...]regulate gap junctions
A: Ca^2+

Q: gap junctions are formed from 12 [...] (6 from each cell) to form one [...]
A: connexins; connexon

Q: [...] prevent passage of material between cells
A: tight junctions

Q: 3 membrane proteins involved in tight junctions are [...]
A: Jam, occuludin, claudin

Q: [...] are transmembrane proteins that are tightly bound to the cytoskeleton
A: cell adhesion molecules (CAMs)

Q: 2 categories of CAM molecules
1. [...]: cell-cell adhesion
2. [...]: cell-ECM adhesion
A: homophilic; heterophilic

Q: 2 types of homophilic CAMs
1. [...] - Ca^2+ independent
2. [...] - Ca^2+ dependent
A: Ig-superfamily; Cadherins

Q: cadherins have a single [...] domain and a C-terminal tail that can associate with keratin or actin cytoskeleton
A: transmembrane

Q: - cadherins forms [...] when bound to keratin
- cadherins forms [...] when bound to actin cytoskeleton
A: desmosomes; adherens junctions

Q: many adherens junctions form contractile [...] belt
A: circumferential

Q: the [...] is a complex mix of secreted moelcules that all cells interact with
A: extracellular matrix (ECM)

Q: the [...] and connective tissue contribute to ECM
A: basal lamina

ECM functions
1. anchoring cells to maintain tissue structure
2. provides biomechanical properties (stiffness/elasticity)
3. controlling cellular polarity, survivial, differentiation, fate
4. acts as resevoir for growth factors
5. enables/disables cell migration

Q: ECM proteins
1. [...] - absorb water to provide tissue resiliency
2. [...] - provide strength and support
3. [...] - recrogized by integrins to allow for cell migration
A: proteoglycans; collagen; fibronectin

Q: integrin is a [...] transmembrane protein with [...] subunits
A: heterodimer; alpha and beta

Q: integrins on cell surface binds to [...] in protein
A: RDG (Arg, Gly, Asp)

Q: integrin recognizes specific substraces in ECM
1. integrin binds to intermediate filaments to form [...]
2. integrins binds to actin network to form [...]
A: hemidesmosomes; focal adhestions

Q: integrins are [...] when bent
A: inactive

Q: selectins recgonizes [...]
A: oligosaccharides

Q: selectins participates in leukocyte [...] - white blood cell leaving blood stream
A: extravasation

leukocyte extravasation
1. endothelial cells receive signal from infection
2. endothelial cells secrete p-selectin to bind to sugar to slow leukocyte down
3. endothelial cell secretes PAF to bind PAF-receptor on leukocyte
4. PAF activates integrin on leukocyte
5. integrin binds to RGD in ICAM for adhestion
6. leukocyte squeezes between endothelial cells