Ch. 18 Catalytic Receptor Signaling

Question 1

What are the signaling molecules in catalytic receptor signaling

Answer 1

Growth factors, cytokines (IL-6, TNF-alpha), peptide hormones

Question 2

What are the receptors like in catalytic receptor signaling

Answer 2

single-chain transmembrane proteins

Question 3

catalytic receptor signaling is regulated by ____ kinases and ______ phosphatases

Answer 3

tyrosine kinases

tyrosine phosphateses

Question 4

What do tyrosine phosphateses do

Answer 4

dephosphorylate

Question 5

What pathways use receptors with tyrosine kinase activity

Answer 5

epidermal growth factor
platelet-derived growth factor
vascular endothelial growth factor
peptide hormones (i.e. insulin)

Question 6

structure of tyrosine kinase receptors

Answer 6

2+ single transmembrane proteins are associated each protein having 3 domains

Question 7

what does the “effector domain” of the tyrosine kinase receptor contain

Answer 7

enzyme with tyrosine kinase activity

Question 8

What are two types of intracellular adaptor proteins are recruited by phosphotyrosines

Answer 8

SH2 and SH3

Question 9

Ras is an example of a catalytic receptor signaling protein true or false?

Answer 9

True

Question 10

STAT is an adaptor protein that contains SH2 and is found bound to the membrane T or F?

Answer 10

False - STAT is found in the cytoplasm

Question 11

The STAT protein, once phosphorylated, forms a dimer and translocates to the membrane Tor F

Answer 11

False - it translocates to the nucleus to induce transcription

Question 12

PI 3 kinase pathway - explain it

Answer 12

1. ligand binds causing dimerization of receptor and phosphotryrosines
2. PI3 kinase binds to phosphotyrosines and is activated
3. activated PI3 kinase phosphorylates inositol phospholipids (PIP2 to PIP3
4. AKT is recruited by PIP3
   5 Akt phosphorylates Bad. this inactivates Bad and prevents cell apoptosis

Question 13

What dephosphorylates PIP3

Answer 13

PTEN

Question 14

What is the end result of the PI3 Kinase pathway?

Answer 14

inactivation of Bad proteins

Question 15

Src family have their own tyrosine kinase activity T or F

Answer 15

False the y do not and have to activate other tyrosine kinases in the cytoplasm

Question 16

what three domains do the SRC family of tyrosine kinases contain? Of the three which contain kinase activity?

Answer 16

SH1, SH2 and SH3

SHi - contains kinase activity

Question 17

Src kinases are an important modulator of cell adhesion and cell cycle regulation T or F

Answer 17

True

Question 18

What is the relationship between JAK and STAT proteins?

Answer 18

JAKs make phosphotyrosines

STATs bind to the phophotyrosines

Question 19

Where do phosphorylated (active) STATs translocate to?

Answer 19

The nucleus

Question 20

What does CRP have to do with insulin in muscle cells?

Answer 20

CRP abnormally phosphorylates IRS-1 on 2 serine residues causing it not to signal properly.