Cell Signalling

Question 1

How does a signal get to a response

Answer 1

Signal

Receptor

Transducers eg sm

Effectors which cause response

Response

Question 2

What can transducers do

Answer 2

Amplify signal from receptor

Question 3

Give example of effectors

Answer 3

Tf, metabolism enzymes eg glycogen synthase, cytokine

Question 4

What is cross talk

Answer 4

Overlap in signals where 2 receptor signals can have same transducer eg same sm camp but cause diff responses

Question 5

How does transducer determine which signal should work in cross talk

Answer 5

Affinity of binding affects it (if bound more then this signal is transduced) and different trigger levels eg diff levels of phosphorylation

Question 6

What are the 3 types of signal

Answer 6

Endocrine for long distance in BV

Paracrine

Autocrine

Question 7

Give example of paracrine signalling

Answer 7

Tgf b release

Question 8

What type of molecules use cell surface receptors

Answer 8

Hydrophilic eg Nt, cytokines, adrenaline

Question 9

What binds ic

Answer 9

Hydrophobic eg steroid oestrogen hormone, NO

Question 10

What are the 3 cell surface receptors

Answer 10

Ion channels (ionotropic) (ligand, voltage, mech)

Gpcr (metabotropic)

Enzyme linked receptors eg rtk

Question 11

Which cell surface receptor is quickest showing signals have different speeds of onset

Answer 11

Ion channels (milliseconds)

Question 12

Which is the slowest cell surface receptors

Answer 12

Enzyme linked

Question 13

What 2 effects do gpcr have

Answer 13

Affect permeability of ion channels eg ca

Or

Regulate enzyme activity which produce secondary messengers eg adenylyl cyclase

Question 14

which gpcr subunit holds and exchanges gtp for activation

Answer 14

A

Dissociates from b and y

Question 15

How many passes do gpcr have in transmembrane vs enzyme linked

Answer 15

7 vs 1

Question 16

What is the ic catalytic domain in rtk

Answer 16

Tyrosine kinase domain

Question 17

What would binding to rtk cause

Answer 17

Dimerisation (unless igf insulin receptor which is already a dimer) and autophosphorylstion

Question 18

What are gpcr usually called

Answer 18

Serpentine

Question 19

Is the n terminal of gpcr ic or EC

Answer 19

EC and c domain is ic

Question 20

Which 2 enzymes are phos and regulated by gpcr a subunit

Answer 20

Phospholipase c (ip3 and dag production ) and adenylyl cyclase (camp production )

Question 21

Give example of pka activity activated by camp eg when glucagon binds

Answer 21

Phosphorylation of glycogen phosphorylase kinase

Which activates phosphorylase a

(Blocks glycogen synthase)

Question 22

What does dag activate

Answer 22

Pkc

Question 23

What does secondary messenger cgmp do

Answer 23

Activates pk g eg for smooth muscle relaxation

Question 24

Give example of a rtk which needs dimerised

Answer 24

Egf receptor

Question 25

What allows specific protein binding and phos on the tyrosine kinase residues

Answer 25

The aa sequence flanking the tyrosine residue binding site

Question 26

Which gpcr needs extra fast activation and slow deactivation

Answer 26

Rhodopsin for light change

Question 27

Which gpcr needs slow activation

Answer 27

B2

Question 28

How is amplification usually by

Answer 28

Increase in secondary messengers

Question 29

What is the exception to amp

Answer 29

Rhodopsin which reduces cgmp