Lecture 11: Tissue Architecture Flashcards
What is more stable - a single protofilament or multiple protofilaments?
Multiple Protofilaments
-single ones are thermally unstable
Why might intermediate cytoskeletal filaments be resistant to stretching forces?
Lateral contacts dominate in the organization of fibers, preventing stretching
-Rope like properties
What are the three types of Cytoskeletal Filaments?
- Intermediate Filaments
- Microtubules
- Microfilaments
For intermediate filaments:
What do they do?
Where are they found?
Where are they anchored?
What do they do?
Great Tensile Strength: Enable cells to withstand mechanical stress
- Where are they found?*
1. Cytoplasm of most cells
2. Nuclear lamina (nuclear envelope) - Where are they anchored?*
Anchored to the plasma membrane at cell-cell junctions
What is the configuration of proteins in intermediate filaments?
- 8 staggered tetrameres form a region
- Will stagger to another 8 staggered tetrameric region in the growing strand
- Stabilized by acessory proteins
What causes progeria?
Mutations in nuclear lamina that causes cellular aging
In what three forms are cytoplasmic intermediate filaments found in cellss?
Epithelium: Keratin filaments
CT/Muscle/Glial Cells: Vimentin filaments
Nerve Cells: Neurofilaments
What role do intermediate filaments play in the nucleus?
They form the nuclear lamina
What is the role of microtubules in the cell?
- Vital to organization
- Form the mitotic spindle for chromosome segregation
- Part of cilia and flagella
On what end of a microtubule do you find gamma-tubulin?
The minus end (serves as an anchoring point)
Which end of a microtubule has faster growth?
Plus end
What configuration of protiens makes up a microtubule?
Rings of alpha and beta tubulin stacked on top of each other
What serves as the branching off point for microtubules at the centrosome?
Small rings of gamma-tubulin on the outside of the centrosome matrix
What stablizes microtubules at the distal end?
Microtubule capping protien
What does Taxol do?
Binds and stabilizes microtubules (prevents excess growth)
Microtubules are like taxis for dynein. Taxol keeps those taxis going.