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***What human genetic disease is associated with defects in the nuclear lamina and what is thought to be the reason behind the effects of the mutations?
Progeria is main disease associated with defects in the nuclear lamina. This is due to a mutation which results in a protein that is not able to become part of the nuclear lamina. The lack of the nuclear lamina to work affects the structure of the nuclear envelope, giving an abnormal shape. This is harmful with cell division, as the lamina cannot provide support to the chomosome organization during mitosis.
**What are the types of intermediate filament associated proteins and what are their functions?
- 1. Plectin: rod shaped, works to connect other IFs together, actin and MTs
- 2. Filaggrin: Aggregates keratin on skin surface
- 3. BPAG1: connects Keratin to BPAG2
What is the relationship between cilia, flagella (eukaryotic), and axonemes? What is the role of the basal body in these “organelles”? How do these organelles generate movement?
- Cilia (shorter) and flagella (longer) both play same roles…cell motility, driven by signaling. The beat generated varies between the two also. Axonemes being the functional core of both of these. The axoneme is composed of the 9 doublet microtubules along with 2 central singlet microtubules, surrounded by a membrane. The basal body is the template for the negative end of these microtubules of the axoneme, and it stems out of the basal body from this point.
- Movement is generated by DYNEIN…moves towards negative end (basal body)
Compare and contrast the catalytic activity and movement generation mechanisms of the kinesins dyneins and myosins.
- Memorize chart of functions!!!
- Myosin catalytic activity
For one of the classes of cytoskeleton associated motor proteins, the position of the motor domain within the primary sequence of the protein correlates with directionality. Which class of motor proteins is this? Discuss the evidence that motor position does or does not make a difference.
LOOK @ TEXTBOOK!!!!!
What are the three major classes of motor proteins and what type of filaments does each move along?
- 1.Myosin: Transports vesicles along ACTIN filaments, used for muscle contraction
- 2.Kinesin: Walks towards the plus end of MICROTUBULES, anterograde axonal transport
- 3.Dynein: Walks towards the negative end (retrograde) of MICROTUBULES, motor for cilia and flagella – retrograde axonal transport
Do all motor proteins "walk" in the same direction along cytoskeleton filaments? If no, what is the significance of directionality for the cell? Provide some examples of motors that walk in different directions.
- IE: Myosin 6 moves towards neg, Kinesin 14 moves towards neg, all others towards positive
- The structure of these proteins dictate if they will be moving in the forwards or reverse direction.
- Myosin: most walk towards the barbed (positive) end of actin filaments (Myo 6 goes towards neg). Most of these are dimers, but some monomers
- Kinesin: most walk towards the Positive end, except for 14, which is C terminal directed, walking towards the negative end. Most dimerize except for Kinesin 3 (monomer)
- Intracellular movement of organelles, chrom
- Dyneins: mostly all walk towards negative end of microtubules. All are dimers, or trimers
- Inracellular as above, but retrograde