Cell motility Flashcards
the motor proteins Kinesin and Dynein are microtubules or microfilaments?
microtubules
the motor protein myosins are microtubules or microfilaments?
microfilaments
what is an example of a cell that moves?
neutrophils: move to site of infection and engulf foreign invaders
intracellular components move: microtubules of the mitotic spindle play a role in the ??? of chromosomes during cell division
separation
To generate movement, MTs and MFs provide a scaffold for motor proteins that produce motion at the ??? level
molecular
the following describes Microtubule-based motility or microfilament based motility?
- transport of organelles and vesicles
– Formation of mitotic and meiotic spindles
– fast axonal transport in neurons
– sliding of MTs in cilia and flagella
microtubule-based motility
the following describes Microtubule-based motility or microfilament based motility?
- muscle contraction
– cell shape changes and migration
– cytoplasmic streaming
microfilament-based motility
motility systems couple ATP hydrolysis to changes in shape and attachment of ??? i.e. they convert chemical energy into mechanical work
the motor proteins
motility systems undergo cycles of ATP hydrolysis, ADP release and aquisition of new ATP, driven by ???
motor proteins
TRUE or FALSE: motor proteins have common structural features and can move along cytoskeletal filaments for significant distances
TRUE
motor proteins move BI-directionall or UNI-directionally (?) across their cytoskeletal track in a stepqise manner. dynamic instability regulates this signalling
unidirectionally
the lever domain of a motor protein transduces ???
conformational change
Kinesins and Dyneins move along microtubules, transporting organelles and vesicles toward the NEGATIVE or POSITIVE (?) end, considered ‘inbound’ whilst towards the opposite end is ‘outbound’
negative/minus end
Axonal transport: proteins produced in the cell body are transported to the nerve ending = FAST or SLOW?
fast
fast axonal transport involves packaging proteins into vesicles for transport by ??? and cytoplasmic dynein
kinesin I
Kinesin I or cytoplasmic dynein is responsible for the following?
- Involved in ATP‐dependent transport toward the positive end (outbound)
- Called anterograde axonal transport
Kinesin I
Kinesin I or cytoplasmic dynein is responsible for the following?
- Moves particles in the opposite direction to the negative end (inbound)
- Called retrograde axonal transport
Cytoplasmic dynein
Kinesins move towards the plus end of MTs and consist of two dimerised heavy chains and two light chains. The heavy chains contain globular domains that attach to ???
MTs
ADP bound head of DYNEIN or KINESIN (?) binds to tubulin and ADP is displaced for ATP = results in rear head flipping forward which affects the conformation, flipping the linker forward and the lagging head with it to the next tubulin to which it binds. Cycle repeats
Kinesin
Kinesin can move long distances along Microtubules before detaching from it by releasing bound ??? and acquiring a new ATP so that the cycle repeats.
ADP
dyneins are a family of minus end-directed microtubule motors structurally unrelated to the kinesins. They are the LARGEST or SMALLEST motor protein?
largest
Cytoplasmic or axonemal dynein (?) are associated with a protein complex called dynactin, which helps link dynein to cargo
cytoplasmic
Cytoplasmic or axonemal dynein (?) are specialised for the rapid and efficient microtubule sliding movements that drive the beating of cilia and flagella
axonemal dyneine
dyneins follow the general rule of coupling ATP hydrolysis and ??? change to microtubule binding and unbinding resulting in a power‐stroke forward
conformational
