Kruse - Endocrine Receptors and Signaling Pathways DSA

Question 1

In general, what two hormone classes interact with cell surface membrane receptors?

Answer 1

1. amino acid derivatives (dopamine, catcholamines, TH)

2. Peptide hormones

Question 2

In general, what four hormone classes interact with intracellular nuclear receptors?

Answer 2

steroids, thyroid hormones, Vit D, retinoids

Question 3

Name the four main types of receptors.

Answer 3

1. Ligand gated ion channels
2. G-protein coupled receptors
3. Kinase linked receptors
4. Nuclear receptors

Question 4

Which two receptor families initiate trascription?

Answer 4

Kinase-linked and nuclear eceptors (take hours)

Question 5

Hormones that bind to GPCR and effectors

Answer 5

1.  (Gas = stimulate cAMP):
B-adrenergics
LH, FSH, TSH
Glucagon
PTH, PTHrP
ACTH
GHRH, CRH
2.  (Gai = inhibit cAMP)
alpha-adrenergic 
somatostatin
3.  (Gaq and Ga11 = PLC, DAG, IP3, PKC, VCCaC)
TRH, GnRH

Question 6

Hormones that bind to Kinase receptors and effectors

Answer 6

Insulin (RTK)
GH, PRL (cytokine receptor-linked kinase - JAK/STAT and TK, MAPk)
TGF-Beta (serine kinase)

Question 7

Hormones that bind to nuclear receptors

Answer 7

Steroid nuclear receptors bind to Glucocorticoids (GR), MR, estrogen, progesterone, androgens

Question 8

Describe insulin/IGF-1 Tyrosine kinase and GF-TK signaling pathway.
Intrinsic enzymatic activity or not?

Answer 8

RAS/Raf, MAPK –> nucleus

Yes, intrinsic enzymatic activity

Question 9

**Describe cytokine receptor kinase signaling pathway. (for GH and PRL receptors)
Intrinsic enzymatic activity or not?

Answer 9

JAK/STAT —> nucleus

No intrinsic enzymatic activity.

Question 10

Describe TGF-B serine kinase signaling pathway

Intrinsic enzymatic activity or not?

Answer 10

Smad —> nucleus

Yes, intrinsic enzymatic activity

Question 11

Name the four targets for G-proteins and cell signaling

Answer 11

AC
Phopholipase C
Ion channels
RhoA/Rho kinase

Question 12

What is AC responsible for?

Answer 12

cAMP production/activation

Question 13

What is Phospholipase C responsible for?

Answer 13

IP3 and DAG formation

Question 14

What G proteins activate and inhibit AC?

Answer 14

G alpha, s (Gas) = stimulates AC –> cAMP formation

G alpha, i (Gai) = inhibits AC –> decreased cAMP formation

Question 15

What G protein activates PLC? What then happens?

Answer 15

G alpha q (Gaq)

then PLC splits PIP into DAG and IP3

Question 16

After PLC splits PIP into DAG and IP3, what happens?

Answer 16

DAG activates membrane bound PKC

IP3 released into cytosol (water soluble) and acts on IP3 receptor

Question 17

What inactivates cAMP?

Answer 17

phosphodiesterase (PDEs)