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Microtubule functions - Coggle Diagram

- - - - when XMAP215 is inactivated through phosphorylation, it increases the dynamic ability of MT during mitosis
        
        nucleation of MT also increases a lot in mitosis
  - - - MT that is not capturing a kentitochore and can 2 can be found antiparallel to each other
    - - MT attached to kinetochore
      - how attachment occurs
        
        (+) end goes to kinetochore but this part of the MT is still free to move
        
        pulling is done by dynein
        
        pushing is done by the motor protein, CNPE
    - - MT going away from the poles
  - - - uses phorphorylation by aurora on protein Ndc 80
    - - corticol anchor
        
        one side is inactivated and other is activated to move the kinetochores to center
  - - - anaphase A
        
        chromosomes move to the ends
        
        done through disassembly on both ends
      - anaphase B
        
        poles is separating and cell starts elongating
        
        driven by motor proteins
        
        kinesin-5 is in the middle of polar MT moving to their + end to undo the overlap and pushes the poles apart
        
        astral MT dynein is activated, depolymerization the MT and causes the pulling motion of the poles
- - - - binds to the microtubule and have ATPase activity
        to move to the + end
        
        usually used for anterograde transport
        
        ATP hydrolysis causes the kinesin head to undergo conformational change and step forward (16 nm each step)
      - composed of different domains
        
        head
        
        the head domains are always ATPase activity that bind to the microtubule
        
        flexible neck (linker)
        
        stalk (tail)
        
        leads to the light chain
    - - they can bind to cargo
  - - - the classic kinesin structure
        
        kinesin is positioned between and alpha and beta dimer
        
        when not moving they are 8 nm apart
      - regulated as it is inactive when folded
        
        it is activated upon receptor binding
    - - 2 different heavy chains and has a heterodomain for cargo binding
        
        heterodomain is for organelle transport
    - - bipolar with 2 head domains that permit for microtubule sliding
        
        they have a tail domain that overlap between the 2 kinesins
    - - simply a head and neck domain that bind to the MT and remove dimers with ATP hydrolysis
        
        works on both the + and - ends and favors MT disassembly
  - - - ex: acetylation of a lysin residue
- - - - the tail structure does not directly bind to the cargo
      - the dynactin complex
        
        has many components such as actin, Arp1 filament and CapZ
        
        one important protein, dynamitin helps regulate the binding to the cargo and releases when dynein reach the - end
        
        too much dynamitin causes dynactin(protein complex) and dynein to explode apart
        
        150glued binds the complex to the MT but is not a motor
- - - - cilila is 2-10 micro meters
        
        sweeps material across tissues
        
        in both cases the structure is bending/sweeping to move stuff across the cell or moving the cells itself
        
        more abundant than flagella
      - flagella is 10- 2000 micro meters
        
        propels cells
        
        less abundant than cilia
    - - uses cytoplasmic dynein to transport retrograde and anterograde(this is to receive and give signals)
        
        these are the same microtubules that are used for bending (the MT has multi-function)
        
        example
        
        interphase cells with non-motile primary cilium with no axonemal dynein that are important for signaling
        
        the axonemal structure has no axonemal dynein and is only used for signaling
        
        stabilized by acetylated tubulin
        
        this cilium sends out important signals only in interphase
        
        there is no MT present in the center
  - - - 9 doublet rings surrounding the a central pair of singlet microtubules (diff from cytoplasmic ones)
        
        this is the 9+2 array
        
        nexin and other proteins hold the doublets in place
        
        the radial spoke heads does the same thing
        
        axonemal dyenin can also be found such that it is stuck on the A-tubule and extends towards the B-tubule
      - has its own plasma membrane
      - from the basal body, it is a triplet microtubule and becomes a doublet at the transition zone
        
        the center of the basal body or or may not have a singlet in the center
        
        only A+B MT are extension from the basal body
        
        this means the basal body contributes to MT polymerization while the centrioles do not
  - - - the basal body and nexin prevents sliding by holding the MT in place
- - - - conclusion that do move their structures around, ATP is required
    - - inject radioactive aa into the squid axon
        
        radioactive aa is incorporated into protein machinery of the axons
        
        the proteins produced are radioactive and move around the microtubules
        
        because they are radioactive, they can be detected and collected at different sections of the axon
        
        the proteins can be isolated with SDS page
        
        the proteins are detected at different axon segments when waiting different amount of time
        
        3 more items...
        
        injections must repeated while waiting longer to observed where a protein group has migrated to