Signal Transduction
What does Ras stand for
Rat sarcoma virus protein
What is the order of proteins that are in the Ras pathway
Bonus! 100
Ras, Raf, Mek, Erk
Actin filaments (F-actin) spontaneously form from actin monomers (G-actin), held together by what kind of bonds?
Hydrogen Bonds
Microtubulin subunits are heterdimers of alpha and beta tubulin. These dimers stack head to tail to form linear protofilaments. How many of these protofilaments arange together to form a microtubule cylinder?
13
The "head" of a Kinesin motor protein actually act like what body part?
Feet/ Legs
What are the three classes of transmembrane receptors?
BONUS! 100
Gated ion channels
Enzyme-coupled receptors
G-protein-coupled receptors
What are the 3 basic types of secondary messenger molecules?
Hydrophobic, Hydrophilic, and Gases
Describe the characteristics of the plus and minus end of a growing actin filament
+: grow more rapidly
-: grow slowly/lose actin subunits
Centrosomes and spindle pole bodies fall under what category/ name?
Microtubule Organization Centers (MTOCs)
What are the two types of motor proteins for microtubules and the ine type for actin? Also, what ends do they travel towards (+/-)?
Micro: Kinesin (+) and Dynesin(-)
Actin: Myosin (+)
phosphotyrosines can interact with what two types of domains?
SH2 and PTB
Activation of RTKs can result in the recruitment of ___. This can further phosphorylate plasma membrane phospholipid phosphoinositides, creating novel binding sites adjacent to the RTK.
Phosphoinositide-3 kinase (PI 3-kinase)
What is the difference between the T and D form of actin subunits and what are their characteristics?
T: bound to ATP- bind more tightly to each other and favor polymerization
D: bound to ADP- bind less tightly to each other, favor depolymerization
What two proteins facilitate nucleation of microtubules?
y-tubulin and y-tubulin ring complexes (y-TuRCs)
How do Kinesins and Dyneins mechanically differ in terms of ATP and microtubule binding?
BONUS! 100
Kinesins: "foot" binds ATP = tightly bound to tubule
Dyneins: Binds ATP = released from tubule
Breifly explain how the Notch signaling pathway works
Between cells- DSL ligand binds to Notch receptor, a protease cuts the receptor so that he intracellular domain of notch can freely travel to nucleus and affect gene expression.
Briefly explain how receptor tyrosine kinases (RTKs) work to start a signaling pathway
ligand-> two RTKs are pulled together-> activated tyrosine kinase domains cross phosphorylate each other-> increased activity and high affinity binding sites!
Explain what Profilin, Thymosin, ARPs, and Formin do
Profilin: Aids in polymerization on the plus end
Thymosin: Works against polymerization of both ends
ARPS: Create stable base for nucleation, and allow branching
Formin: Binds to plus end, enhances nucleation
Compare and contrast Stathmin, MAPs, and Catastrophin by what they do to microtubule formation
BONUS! 200
Stathmin- prevents polymerization- promotes instability
MAPs- bind, brace, and stabilize
Catastrophin- prys apart protofilaments- destabilizes
Use your arms (and words) to explain how Dyneins are responsible for the motion of cilia and flagella
i judge
Explain or draw the process by which GPCRs are inactivated by a negative feedback loop
Activated GPCR-> stimulates GRK to phosphorylate GPCR-> Arrestin binds to the phosphorylated GPCR-> G protein can't bind to or be activated by GPCR
Draw the Gs/Gi and Gq pathways shown in the notes. First to bring me their paper with it correct gets the points
I judge
What are the 4 main types of actin structures, and what do they generally look like?
BONUS! 300
Stress fibers: Bundles of contractile "cables" in the cytoplasm
Filopodia: Finger-like extensions from the membrane (probe and sense)
Lamellipodia: Broad, sheet-like protrusions from the membrane (move)
Microvilli: tiny finger-like projections (increased surface area)
Explain why Wiscott-Aldrich syndrome (mutations in WASp) result in those affected having immune deficiency.
WASp is responsible for promoting actin fibers in filopodia. Filopodia are necessary to form the immunological synapse.
Explain what tropomyosin and troponin are and how calcium allows for myosin binding and in turn, muscle contraction?
Calcium induces a conformational change in troponin which "levers" tropomyosin out of the way, so that myosin can bind to the binding sites on actin.