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Define motility
Ability of an organism to move independently using metabolic energy
Addition of actin occurs much more rapidly on the _____ end rather than the _____ end.
barbed (+); pointed (-)
Which actin is added to both ends?
High ATP-actin
Which actin is only added to one end? What happens to the other end?
Lower ATP-actin; added to barred (+), removed from pointed (-)
What happens to actin assembly during a steady state?
Constant addition of ATP-actin on barbed end and removal on pointed end (treadmilling)
_____ is the molecular motor of actin
Myosin
What is myosin?
Microfilaments in peripheral regions of the cell
What is myosin Va? What can you refer to it as?
Protein in charge of intracellular transport of vesicles, organelles, and protein complexes along actin filaments. ; molecular motor
Where is Myosin Va found in in the human genome?
MYO5A gene
What can Myosin Va put on itself as it moves?
Carry cargo
How are pigment granules transferred? Where are they transferred from and to?
Myosin Va; microtubules —> microfilaments
What is conventional type II myosin?
Myosin responsible for producing muscle contraction in muscle cells in most animal cell types
Generate force in muscles and non-muscle cells
Describe what conventional myosin looks like
Two heavy chains with globular heads and two light chains
Which part of the type II myosin is required for motor activity?
Head (catalytic sites)
Which portion of the conventional myosin allows proteins to for filaments?
Tail
What is myosin type II also known as?
Conventional myosin
What do myosin II monomers assemble into?
Bipolar myosin filaments
In actin-binding proteins, which part of it is an active region of the cell?
Cell cortex
What do actin-binding proteins affect?
Localized assembly and disassembly of actin filaments, physical properties, interactions with one another, and organelles
Describe the process of actin-binding proteins
meep
How do cells crawl?
Forming a protrusion called lamellipodium
What triggers localized polymerization of actin?
Stimulus at the plasma membrane
When the plasma membrane is stimulated, what is triggered?
Localized polymerization of actin, polarization of cell, and movement towards stimulus
What does the WASP family activate?
A Arp2/3 complex activation
What do activated complexes initiate?
Nucleation of actin polymerization
When side branches form, what pushes the plasma membrane outward?
Complexes
What do lamellipodia have?
Branched, cross-linked filamentous actin network beneath the plasma membrane
Where do ‘traction forces’ occur?
Sites where the cell grips the substrate
What do focal complexes that form near the leading edge of a motile cell do?
Exert traction forces and then disassemble as the cell moves forward.
The _____ of an axon (growth cone) is highly motile.
tip
What are microspikes?
Outward points to the edge of the lamellipodium
What are filopodia?
Elongations that extend and retract during motile activity
What does a growth cone do?
Explore its environment and elongates its axon
Within the lamellipodium, actin ribs are also known as microspikes. When they extend beyond the lamellipodia, they are known as filopodia. Containing microfilaments (actin filaments) cross-linked into bundles by actin-bundling proteins, such as fascia and fimbrin.
yer
What would happen if there was a mutation in a gene that made WASP into a neutrophil?
good question
