Cell Signaling

Question 1

What does absence of signaling cause

Answer 1

Apoptosis

Question 2

5 types of signaling

Answer 2

Endocrine- hormonal, long range. Blood stream
Paracrine- nearby, diffusion
Neuronal- very close, synapses
Contact dependent- cells linked by signal
Autocrine- cell signals self

Question 3

Signal components

Answer 3

Ligand, receptor, intracellular signal proteins, target proteins

Question 4

Is ligand concentration high or low

Answer 4

Low, and affinity is very high

Question 5

Two types of receptor

Answer 5

Cell surface and intracellular. Intra requires small hydrophobic signal like a steroid

Question 6

Domains of intracellular signal protein

Answer 6

Dna binding, ligand binding, transcription activation, inhibitory or promoter

Question 7

Types of cell surface receptors

Answer 7

Ion channel linked(bind to allow ions in), G protein linked (7 pass), and enzyme linked (single pass)

Question 8

Secondary signal protein uses

Answer 8

Turn signal on or off, amplify signal, or split signal

Question 9

Can response proteins do different things with same signal, or same with different?

Answer 9

Yes

Question 10

Which is slower: dna pathway or altered protein pathway

Answer 10

DNA pathway

Question 11

G protein receptor pathway

Answer 11

Receptor binds signal, causing protein to bind G protein. Makes gtp, and splitting trimer into two. Alpha unit activates target and makes gdp, rebinding to trimer

Question 12

cAMP pathway

Answer 12

G protein. Activates a protein that makes cAMP, activates protein kinase A, which goes to nucleus to phosphorylate.

Question 13

Ca signaling pathway

Answer 13

G protein activated. Activates phospholipase C, which releases inositol, opening Ca channel in ER, activating Protein kinase c

Question 14

Enzyme pathways

Answer 14

Generally receptor tyrosine kinase. Involve dimer signals. Which dimerize tyrosine kinase, P itself to make signal complex

Question 15

What do phosphorylation sites on RTKs do?

Answer 15

Serve as protein docking sites

Question 16

What are signal transduction switches and what types?

Answer 16

Turn signal on or off. Kinase type and gtpase type.

Question 17

SRC domains and functions

Answer 17

N and C lobe- ATP between
SH1- kinase
SH2- phosphotyrosine binding 
SH3- protein binding 
SH4- binds membrane

Question 18

SRC pathway

Answer 18

Nonreceptor TKR. Tail Dephosphorylated to open, then loop is phosphorylated, opening catalytic cleft. Three states

Question 19

RAS basics

Answer 19

RTK linked to GTPase. Tethered to membrane.

Question 20

RAS pathway

Answer 20

Activated by GEF, forcing in GTP. Then signals, and GAP induces GTP hydrolysis inactivation, turning off. Activates MAP kinase cascade.

Question 21

JAK-STAT pathway

Answer 21

RTK. Cytokine binds, binding JaK to itself. Then it phosphorylates itself twice, where STAT binds and dimerizes

Question 22

NF-kB path

Answer 22

Activates inhibitor kinase, which degrades inhibitor of NF-kB

Question 23

TGF- b pathway

Answer 23

Type 2 receptor binds signal(BMP), which binds and phosphorylates type 1. Activates smads

Question 24

Wnt pathway

Answer 24

Frizzled binds receptor, activating disheveled, which prevents GSK from degrading beta catenin

Question 25

Hedgehog pathway

Answer 25

Sonic binds, preventing patched from inhibiting smoothened, which prevents GLI from being cut. Normally repressor, now inducer.

Question 26

Cell contact path (Notch)

Answer 26

Delta binds notch, connecting cells. Pulls up notch, allowing cleavage. Lowers notch, further cleavage. Bit inside goes to nucleus. Differentiation.

Question 27

Types of combinatorial action

Answer 27

Integration, divergence, cross talk, specialization.