🦸 Good vs. Bad Guys of Exam 3 🦸

G-alpha-s

🟢 Good Guy: Stimulates adenylyl cyclase to increase cAMP and keep the signal moving.

Phosphodiesterase (PDE)

🔴 Bad Guy: Destroys second messengers like cAMP and cGMP to shut down the party.

PKA

🟢 Good Guy: Activated by cAMP to go into the nucleus and turn on genes for growth and response.

GRK (GPCR Kinase)

🔴 Bad Guy: Phosphorylates the receptor to start the process of shutting it down.

Arrestin

🔴 Bad Guy: Physically blocks the receptor from talking to G-proteins; the ultimate signal "silencer."

Ras

🟢 Good Guy: The essential molecular switch that kickstarts the MAP kinase growth cascade.

MAPK (Erk)

🟢 Good Guy: The final kinase that enters the nucleus to tell the cell to change its behavior or grow.

Caspases

🔴 Bad Guys: The executioners that literally chop up the cell from the inside out.

Cytochrome C

🔴 Bad Guy: Once it escapes the mitochondria it helps build the machine that kills the cell.

Bcl2

🟢 Good Guy: An anti-apoptotic protein that guards the mitochondria to keep Cytochrome C inside.

Bad

🔴 Bad Guy: A pro-apoptotic protein that tries to inhibit Bcl2 so the cell will die.

Akt

🟢 Good Guy: The master survival kinase that inhibits the "bad guys" like Bad to keep the cell alive.

PTEN

🔴 Bad Guy: A phosphatase that destroys PIP3 to stop survival signaling (the "brake" on Akt).

Cohesin

🔴 Bad Guy: The "handcuffs" that keep sister chromatids trapped together until anaphase.

CENP-E (Kinesin-7)

🟢 Good Guy: The motor that helps push chromosomes toward the middle so they can be sorted.

Cyclins

🟢 Good Guys: The essential partners that "wake up" the Cdks to move the cell cycle forward.

APC/C

🟢 Good Guy: In this context a hero because it destroys Securin to finally set the chromosomes free.

Securin

🔴 Bad Guy: The inhibitor that keeps Separase locked up and prevents the cell from finishing mitosis.

Separase

🟢 Good Guy: The "scissors" that cut the cohesin handcuffs to allow sister chromatids to separate.

Wee1

🔴 Bad Guy: The kinase that puts an "inhibitory phosphate" on M-Cdk to keep it from starting mitosis too early.

Cdc25

🟢 Good Guy: The phosphatase that removes the inhibitory phosphate to finally trigger the start of mitosis.

CKI (p21/p27)

🔴 Bad Guys: Inhibitor proteins that sit on Cdks and stop the cell cycle in its tracks.

p53

🟢 Good Guy: Known as the "Guardian of the Genome." It stops division when it sees DNA damage.

Mad2

🔴 Bad Guy: The "stoplight" at the spindle that prevents anaphase until every chromosome is ready.

Cdc20

🟢 Good Guy: The key that unlocks APC/C so the cell can finally finish mitosis.