Question/Term | Answer/Definition |
Properties of Intermediate Filaments | Polarity: None
Functions:
-Structure
-Shape
-Formation of nuclear lamina and scaffolding
-Strengthening of nerve cell axons
-Keeping muscle fibers in register |
Properties of Microtubules | Monomers: Alpha-Tubulin and Beta-Tubulin
Polarity: +/- ends
Functions:
-Organization of share and polarity
-Chromosome movements
-Intracellular transport
-Cell motility |
Elements of the Cytoskeleton | 1. Microtubules (MTs)
2. Microfilaments (MFs)
3. Intermediate filaments (IFs) |
Properties of Microfilaments | Monomers: G-actin
Polarity:
+/- ends
Functions:
-Muscle contraction
-Cell locomotion
-Cytoplasmic streaming
-Cytokinesis
-Shape and transport |
Types of Microtubules | 1. Cytoplasmic
2. Axonemal |
Bacterial-Tubulin Equivalent | Ftz |
Bacterial Intermediate Filament Protein Equivalent | Crescentin |
Protofilament, Heterodimer, Tubulin Monomers | Protofilament: The whole heterodimer and monomer(alpha or beta monomers) all together.
Heterodimer: Alpha and Beta monomers.
Monomer: An alpha or Beta particle. |
Bacteria Actin Equivalent | MreB |
Vinblastine and Vincristine | -Affect MTs
-Aggregate tubulin heterodimers |
Phallodin | -Affects MFs
-Binds and stabilizes assembled MFs
- (+) No polymerization
- (-) No depolymerization |
Taxol | - Affects MTs
- Stabilizes MTs
- (+) No polymerization
- (-) No depolymerization
-Everything is stable. |
Latrunculin A | - Affects MFs
- Sequesters actin monomers
"JAIL" (Puts monomers separately in a corner or "jail" to keep from polymerizing. |
Microfilament Actins | - G-actin
- F-actin
- G-actin: Monomers of F-actin
- F-actin: Polymerized G-actin which form filaments. |
Cytochalasin D | - Affects MTs
- Prevents addition of new monomers to plus ends ("thinks plus end is ugly and won't hook up with it") |
Colchicine Colcemid | - Affects MTs
- Binds tubulin monomers, inhibiting self assembly (binds to both/either alpha or beta monomers and won't let them polymerize). |
Nocadazole | - Affects MTs
- Binds to Beta-tubulin, inhibiting polymerization (thus will not allow the monomers to bind). |
Singlet MTs | - 13 profilaments
- Cytoplasmic MTs |
Doublet MTs | - One of the 13 protofilament part and one additional incomplete 10 or 11 protofilament part.
- Ex: Cilia and flagella |
Triplet MTs | - One 13 protofilament part and two additional 10 or 11 protofilament parts.
- Ex: Basal bodies and centrioles |
Microtubule Nucleation | - When oligomers (groups of aggregated tubulin heterodimers) form nuclei from which MTs grow. |
Microtubule Elongation | - The stage in which nucleated MTs grow by the addition of subunits at either end. |
MT Lag Phase | Nucleation |
MT Elongation Phase | - Tubulin heterodimers are added to the nucleated MT and it grows. |
MT Plateau Phase | - MT assembly and disassembly are balanced. |
MT Critical Concentration | - The tubulin heterodimer concentration at which MT assembly is exactly balanced with disassembly. |
MT Plus End | - The rapidly growing end of the MT. |
MT Minus End | - The slowly growing end of the MT
OR
- The depolymerizing end when the critical concentration is reached for the plus end, but not the minus end. |
Treadmilling | - When a given tubulin molecule incorporated at the plus end is displaced progressively along.
-The MT eventually are lost by depolymerization at the opposite end. |
MAPs | -MT-associated proteins.
-MAPs increased MT stability and can affect the density of bundles of MTs.
-Tau: Causes MTs to form tight bundles in axons.
-MAP2: Causes the formation of looser bundles of MTs. |
Tau | Causes MTs to form tight bundles in axons. |
MAP2 | Causes the formation of looser bundles of MTs. |