Lecture 11 + 12: Biological Signaling Molecules - Drug Targets

Question 1

What are the 2 ways intercellular signalling can take place?

Answer 1

Secreted molecules and plasma membrane-bound molecules

Question 2

What are the 3 types of signalling molecules and their respective type of signalling?

Answer 2

Local chemical mediators - paracrine
Hormones - endocrine
Neurotransmitters - synaptic

Question 3

What are the 2 types receptors?

Answer 3

1. Cell surface receptors

2. Intracellular receptor

Question 4

How do cell surface receptors work?

Answer 4

Cell surface receptor recognizes hydrophilic signalling molecules and translates message into the cell

Question 5

How do intracellular receptors work?

Answer 5

Small hydrophobic signalling molecule diffuses into cell towards intracellular receptor

Question 6

What is a receptor?

Answer 6

Molecule that recognizes specifically a second molecule of a family of molecules and which in response to ligand binding brings about regulation of a cellular process

Question 7

What is a ligand?

Answer 7

Any molecule that binds specifically to a receptor site

Question 8

What is a agonist?

Answer 8

Ligand that produces activation of a receptor when bound

Question 9

What is a antagonist?

Answer 9

Ligand that binds to receptor site and does not cause activation, opposing the actions of an agonist

Question 10

What are 8 roles of receptors in cellular physiology?

Answer 10

1. Signalling
2. Neurotransmission
3. Cellular delivery
4. Control of gene expression
5. Cell adhesion
6. Modulation of immune response
7. Sorting of intracellular proteins
8. Release of intracellular calcium stores

Question 11

What are 2 types of acetylcholine receptors?

Answer 11

Nicotinic and muscarinic

Question 12

What is an agonist of nicotinic Ach receptors?

Answer 12

Nicotine

Question 13

What is a agonist of mAchR?

Answer 13

Muscarine

Question 14

What are 4 ways of transducing extracellular into intracellular signals?

Answer 14

1. Membrane-bound receptors with integral ion channels
2. Membrane-bound receptors with integral enzyme activity
3. Membrane-bound receptors which couple to effectors through transducing proteins
4. Intracellular receptors

Question 15

What is the structure of the classic receptor family?

Answer 15

5 similarly structured subunits in a receptor

Question 16

What are 4 examples of receptors from the classical receptor family?

Answer 16

nAChR, GABA, glycine receptor, glutamate receptors

Question 17

What is an example of a receptor not from the classical receptor family?

Answer 17

IP3 receptor

Question 18

What is the structure of membrane-bound receptors with integral enzyme activity?

Answer 18

Binding domain N terminal on the outside, catalytic domain with C terminal on the inside

Question 19

What are 2 examples of membrane-bound receptors with integral enzyme activity?

Answer 19

ANP receptors linked directly to guanylyl Cyclase

Growth factor receptors linked directly to tyrosine kinase

Question 20

How do tyrosine kinase-linked receptors work?

Answer 20

Ligand binds to receptor on extracellular domain, nearby kinase linked receptors couple to become an active dimer, beginning auto-phosphorylation where tyrosine residues cross phosphorylated and become activated, proteins bind to them and further relay signals to target

Question 21

What is the structure of membrane-bound receptors that signal through transducing proteins?

Answer 21

Seven transmembrane domain (7TMD) receptors

Question 22

What is the structure of G-protein coupled receptors?

Answer 22

Binding domain extracellular and in the middle of the 7 transmembrane domains, G-protein coupling domain intracellular

Question 23

What is the structure of intracellular receptors?

Answer 23

Binding domain at C terminal and DNA-binding domain

Question 24

How do intracellular receptors work?

Answer 24

Hormones enter cell and binds to receptor, causing receptor to change conformation, exposing regions that have DNA-binding activity, receptor binds next to genes and alter level of transcription

Question 25

What are 3 examples of intracellular receptors?

Answer 25

Cortisol receptor, oestrogen receptor, progesterone receptor