Receptors In Cell Signalling, Receptor Structure And Common Structural Motifs (6) Flashcards Preview

ESA 2 Membranes and Receptors > Receptors In Cell Signalling, Receptor Structure And Common Structural Motifs (6) > Flashcards

Flashcards in Receptors In Cell Signalling, Receptor Structure And Common Structural Motifs (6) Deck (25)
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0

What are the two main ways of intracellular signalling?

- Via secreted molecules
- Via plasma membrane-bound molecules

1

What is paracrine signalling?

- Signalling cell secretes local mediators to multiple target cells

2

What is endocrine signalling?

- Signalling cell secretes hormone into blood stream to target cells

3

What is synaptic signalling?

- Neurotransmitters across synaptic clefts.

4

What are the two main types of molecules that are involved in intracellular signalling and how do they reach the target cell?

- Steroid
- Thyroid
- Via carrier proteins in the blood diffusing across membrane

5

What is the definition of a receptor?

- A molecule that recognises specifically a second molecule/family of molecules
- In response to ligand binding, regulation of cellular processes occur.

6

What role does a receptor have when unbound?

- Nothing

7

What is a ligand?

- Any molecule that binds specifically to a receptor site.

8

What do ligands do?

- May produce activation of a receptor - agonist
- May combine with a receptor site without causing activation - antagonist

9

Give comparisons of receptor affinity to enzyme affinity to ligand binding.

- Receptor: 10^-9M - 10^-6M
- Enzyme: 10^-6M - 10^-3M

10

How are receptors classified?

- Via specific physiological signalling molecule (agonist) recognised

11

How are receptors subclassified?

- Affinity (tightness of binding) of a series of antagonists

12

What are the agonists of the following:
- Nicotinic
- Muscarinic

- Nicotine
- Muscarine

13

What do the following muscarinic receptor subtypes bind to?
- M1
- M2
- M3

- M1: Pirenzipine
- M2: Gallanine
- M3: Hexahydrosiladiphenol

14

What is the difference between a receptor and an acceptor?

- Receptor: Silent at rest & antagonist binding stimulates a biological response
- Acceptor: Operates in absence of ligand & ligand binding alone produces no response

15

How are extracellular signals transduced into intracellular signals?

- Membrane bound receptors with integral ion channels
- Membrane bound receptors with integral enzyme activity
- Membrane bound receptors which couple to effectors via transducing proteins
- Intracellular receptors

16

Give examples of membrane bound receptors with integral ion channels.

- nAChR: gated Na/K/Ca channels
- GABA: gated Cl channels
- Glycine: gates Cl channels
- Glutamate (NMDA/AMPA): gated Ca

17

Describe the look and function of membrane bound receptors with integral enzyme activity.

- N end outside cell - binding domain
- C end inside cell - catalytic domain

18

Give examples of membrane bound receptors with integral enzyme activity.

- Platelet derived growth factor receptor (PDGF)

19

Describe how signalling via tyrosine kinase linked receptors works.

- Receptor + agonist -> agonist bound receptor with auto phosphorylation -> a) Direct to enzymes OR b) Uses transducer to reach enzyme.

20

How do insulin receptors work?

- alpha molecules bind to beta transmembrane receptors via the insulin binding domain
- This activates the tyrosine kinase domain to cause an effect

21

What is the role of G-protein coupled receptors?

- They produce both Gs (stimulatory) and Gi (inhibitory)
- These allow for regulation of target cell activity

22

What does G proteins stand for?

- GTP binding regulatory proteins

23

What is the role of G proteins in 7TMD receptors

- Adrenaline binding to beta-adrenoreceptors activates ATP cAMP via Gs
- ACh binding to M2 muscarinic ACh receptors simulate K channel opening via Gi

24

How can amplification in cellular signalling occur?

- Receptors stimulated and release GDP to attach to another protein and form a protein-GTP complex which produces cAMP
- cAMP stimulates protein kinase release to stimulate enzyme production
- Product of this is huge amplification