W3: Signal Transduction

Question 1

Beta adrenergic receptor (B AR) is an example of ____, activated by ligands ___ (___).

Answer 1

GPCR, epinephrine (adrenaline)

Question 2

Epinephrine (adrenaline) causes physiological changes such as ___ and ___.

Answer 2

Increased CO, bronchodilation

Question 3

Selectivity: low affinity of ligand-receptor means low/high Kd (dissociation constant).

Answer 3

high

Question 4

Isopreterenol is an agonist/antagonist drug that activates/blocks beta adrenergic receptor (B AR).

Answer 4

Agonist (like epinephrine/adrenaline), activate

medication used for the treatment of bradycardia (slow heart rate), heart block, and rarely for asthma. It is a non-selective β adrenoreceptor agonist that is the isopropylamine analog of epinephrine (adrenaline). (Wikipedia)

Question 5

Propranolol is an agonist/antagonist drug that activates/blocks beta adrenergic receptor (B AR).

Answer 5

Antagonist, block

“Propranolol is a beta-blocker used to treat high blood pressure, irregular heartbeats, shaking (tremors), and other conditions”

Question 6

In B AR signaling, second messenger ____ is made by effector protein ___ ___.

Answer 6

cAMP, Adenylyl cyclase

Question 7

In B AR signaling, adenylyl cyclase is activated by ___ attached to GDP/GTP.

Answer 7

G-protein, GTP

Question 8

List five mechanisms of attenuation of B AR signaling

Answer 8

1) Return from GTP to GDP (hydrolysis by GAP)
2) Reduce cAMP to AMP (phosphodiesterase)
3) Inactivate PKA
4) Receptor desensitization (modify receptor)
5) Ligand-receptor degradation (endocytosis)

Question 9

PTH is released when parathyroid detects low/high blood calcium level

Answer 9

low

Question 10

PTH acts on ___ and ___ to increase/decrease blood calcium.

Answer 10

Kidney, bone, increase

Question 11

Hypoparathyroidism is when there is low/high Ca2+, low/high PTH. Causes are ____, ____.

Answer 11

Low, low; parathyroid damage, congenital

When calcium is low, PTH is supposed to go up. This means parathyroid is malfunctioning.

Question 12

Hypoparathyroidism causes symptoms like ___, ___, ___ and can be treated with ____, ____.

Answer 12

Cramping, twitching, spasms;

Ca2+ supplement, vitamin D

Question 13

Pseudohypoparathyroidism: low/high Ca2+, low/high PTH

Answer 13

Low, high

This means PTH production is working correctly but signaling is not.
Haploid sufficiency; one copy mutation (G alpha gene), presentation is less than normal; half as much protein so more PTH won’t help

Question 14

Nicotine/Ach receptor (NR) is an example of ___, whose ligand is ___ (or ___).

Answer 14

Ligand-gated ion channel receptor, Ach (or nicotine)

Question 15

Autoimmune disease that destroys Nicotine/Ach receptors is called ___ ___.

Answer 15

Myasthenia gravis

Question 16

The most common type of enzyme-linked (catalytic) receptor is ___.

Answer 16

RTK - receptor tyrosine kinase

Question 17

Brain cancer (glioblstoma multiforme) can be caused by ___, a RTK. Treatment can be administering ____ ____ drug.

Answer 17

EGFR - epidermal growth factor receptor; EGFR inhibitor

Question 18

What is RAS and what pathway is it involved in?

Answer 18

RAS is a regulated GTPase in RTK pathway.

Question 19

What connects phosphorylated RTK and GEF?

Answer 19

Adaptor protein

lack any intrinsic enzymatic activity themselves, instead mediating specific protein-protein interactions that drive the formation of protein complexes (Wikipedia)

Question 20

RAS regulation:

GTP –> GDP by ___ (inactivate)

Answer 20

GAP: GTPase Accelerating Protein

Question 21

RAS regulation:

GDP dissociated by ___ (lead to activation of RAS)

Answer 21

GEF - Guanine nucleotide Exchange Factor

Question 22

Feedback signaling: FSH produced in (A) and act on (B) cell, which produces estrogen. Estrogen inhibits A from producing FSH.

Answer 22

A. Pituitary gland

B. Ovarian follicular cells

Question 23

Glycogenesis is facilitated by enzyme ____ ____, which is activated/inhibited by GSK by default (without insulin).

Answer 23

Glycogen synthase, inhibited

Question 24

In the presence of insulin, AKT is activated and ultimately activates/deactivates glycogen synthase.

Answer 24

activates

Question 25

AKT/GSK/GS is inhibitor of inhibitor, increasing/decreasing glycogenesis.

Answer 25

AKT, increasing

Question 26

In insulin signaling, AKT promotes increase in blood glucose by doing 2 things:

Answer 26

1) Promoting glycogenesis (by activating Glucogen Synthase)

2) Increasing GLUT4 on plasma membrane

Question 27

Muscle cells and fat cells have GLUT#, mobilized by kinase ___ (inhibitor of inhibitor).

Answer 27

4, AKT (aka PKB)

Question 28

Receptor types for insulin and glucagon:

Answer 28

Insulin receptor: TKR

Glucagon receptor: GPCR

Question 29

Through ___ signaling pathway, glucagon activates PKA, activating ____ ____ to increase glycogenolysis.

Answer 29

GPCR, glycogen phosphorylase

Question 30

Glucagon increase glycogenolysis AND ________ in the liver.

Answer 30

Gluconeogenesis.

Question 31

_____, a sugar-coated hemoglobin, is a diagnostic marker because hyperglycemia leads to _____ of protein in a non-enzymatic way.

Answer 31

HbA1c, glycosylation

Question 32

What are three ways to decrease blood glucose?

Answer 32

1) Speed up storage of glucose from blood (fat, muscle, liver, pancreas)
2) Slow uptake of glucose into the blood (intestine, kidney)
3) Inhibit gluconeogenesis in liver

Question 33

Name four types of receptors and their examples:

Answer 33

GPCR (B AR - epinephrine/adrenaline, PTH)

Ligand-gated channel (NR - Ach/nicotine)

Enzyme-linked receptor (RTK - insulin)

Nuclear receptor (steroid)

Question 34

How are hypoparathyroidism and pseudohypoparathyroidism different?

Answer 34

Hypo - low PTH level causes low blood Ca2+ (problem with parathyroid)

Psuedo - low Ca2+ but parathyroid is fine (normal PTH), meaning there’s problem with signaling

Question 35

___ and ___ are regulators of RAS, which is a ____.

Answer 35

GEF, GAP, GTPase.

Question 36

RAS effector _____ is a kinase that activates ___.

Answer 36

RAF, MAPK

Question 37

Nuclear receptor + lipid-soluble hormone = __ __

Answer 37

Transcription factor

Question 38

Glycogenesis is facilitated by enzyme ___ ___, and glycogenolysis by ___ ____.

Answer 38

Glycogen synthase, glycogen phosphorylase

Question 39

GLUT4 is found in ___ and ___.

Answer 39

Muscle and fat

Question 40

GLUT2 is found in ___ and ___.

Answer 40

Liver and pancreas

Question 41

Na+/glc symporter is found in __ and __.

Answer 41

Gut and kidney

Question 42

Upon insulin signaling, GLUT# is mobilized to the cell membrane for increased uptake of glucose.

Answer 42

4

Question 43

Name two GTPas regulators

Answer 43

GAP (activate)

GEF (inactivate)

Question 44

A treatment for diabetes, ___ is a drug that induces insulin release from pancreas

Answer 44

Secretagogue