Cytoskeleton, junction, ECM Flashcards
What are the three main cytoskeletal components?
1-Microfilaments
2-Intermediate filaments
3-Microtubules
What are microfilaments composed of and what do they do?
composed of actin. act as structural (shape) component of cell (6-8 nm in diameter)
What are intermediate filaments made of and what do they do?
- sometimes vimentin (mesenchymal) or cytokeratin (10nm diameter)
- anchors cell (as in desmosomes)
- bundles are called tonofilaments
What are microtubules made of and what do they do?
- Made of tubulin in hollow tubes (25nm diameter)
- “monorail system” of the cell via kinesins and dynein
What are the 6 cell attachments?
1-Tight Junction 2-Zonula adherens 3-Focal adhesion 4-Desmosomes 5-Hemidesmosomes 6-Gap Junctions
Claudin, Occluding, and Jam interact homotypically binding to actin microfilaments by forming what?
Tight junction (maintains cell polarization and controls movement of “stuff”)
Caherins (outside) and Catinins (inside) form a band like complex that hold cells together by forming what?
Zona adherens (20 nm gaps)
Cadherins are dependent on what cation?
Ca +2
What do cinvulin and actinic attach to in zone adherens?
actin filaments
Integrins (replace cadherin as a transmembrane component) associating with ECM form what?
Focal Adhesion junctions
Vinculin, actinin and talin attach to what in focal adhesion junctions?
actin filaments
Cadherins (outside) referred to as desmoglein and desmocollin along with catinins (inside) like the “plaks” interact heterotypically to form lines externally and plaques internally called what?
Desmosomes (Gaps of 25nm)
*resist shear forces
What structural component to desmosomes attach to?
intermediate filaments
Interns attached to basal lamina by intern-laminin and collagen 7 attach to intermediate filaments to form what?
hemidesmosome
Aqueous pores used to pass small ions, molecules and electrical signals are called what?
Gap junctions
*made of 6x connexins called a connexon
50-100 nm thick, basal lamina connects what?
epithelium to connective tissue
What are the 3 zones of basal lamina?
1-Lamina lucida (Laminin, entactin, integrins)
2-lamina densa (collagen 4/chicken wire)
3-lamina fibroreticularis (usually collagen III, epithelial tissues)
What amino acid helps hold the strands of collagen form a triple helical structure and ultimately a fibril?
Proline and lysine
What type of collagen is dentin, pulp, and cartilage?
- Dentin: Type I, some Type III
- Pulp: Type I and III
- Cartilage: Type II
the overlap of microfibrils align in a parallel, staggered fashion causing what appearance?
banded appearance
*crystals are typically in the gaps
Glycoproteins Fibrillin-1 and 2 form scaffold to which what accumulates?
Elastin fibers
*elastin is a fibroblast product and binds growth hormone
proteoglycans and glycoproteins make up a gel like, highly hydrated substance called?
Ground substance
What main component of ground substance helps sequester water and growth factors?
proteoglycans made up of GAGs and a protein core
What helps break down matrix for remodeling?
MMPs
