Day 3 - Part 3

What are kinases

Enzymes that add phosphate groups to proteins

What is the effect of phosphorylation on proteins

It can turn proteins on or off

What are phosphatases

Enzymes that remove phosphate groups

What is the role of phosphatases

Turn signaling off

What are GTPases

Molecular switches that cycle between active and inactive states

What determines whether a GTPase is active or inactive

The bound nucleotide GDP or GTP

What is the inactive state of a GTPase

Bound to GDP

What is the active state of a GTPase

Bound to GTP

What does GEF do

Promotes exchange of GDP for GTP to activate the GTPase

What does GAP do

Accelerates GTP hydrolysis to inactivate the GTPase

What is Ras

A small GTPase involved in signaling pathways

Why are GTPases considered binary switches

They are either fully ON or fully OFF

What are second messengers

Small molecules that rapidly spread signals inside the cell

What are examples of second messengers

cAMP calcium ions and IP3

What is the purpose of second messengers

Amplify and propagate signals within the cell

What is signal integration

The process of combining multiple signals to produce a response

What is AND logic in signaling

Requires multiple signals for activation

What is OR logic in signaling

Either signal can activate the pathway

What is NOT logic in signaling

One signal inhibits another

What is coincidence detection

Requires multiple signals at the same time

What is summation in signaling

Multiple signals add together to strengthen output

What is crosstalk between pathways

Interaction between different signaling pathways

How can pathways interact during crosstalk

They can enhance or inhibit each other

What are scaffold proteins

Proteins that organize signaling components together

Why are scaffold proteins important for specificity

They keep correct proteins together and prevent incorrect interactions

How do scaffold proteins increase sensitivity

Increase local concentration of signaling molecules

How do scaffold proteins increase efficiency

Reduce diffusion time for signaling components

What is liquid liquid phase separation LLPS

Formation of localized signaling hubs

What is signal amplification

Increase in signal strength through cascades

How does amplification occur in signaling

One receptor activates many proteins and cascades multiply the signa