Signal transduction pathways

Question 1

endocrine

Answer 1

cell to blood to target cell

Question 2

paracrine

Answer 2

cell to target cell

Question 3

autocrine

Answer 3

cell to same cell

Question 4

contact dependant

Answer 4

cell to cell by membrane attached proteins

requires direct contact

Question 5

signal transduction

Answer 5

requires amplification of the signal within the cell to trigger the response
will require a system to slow/stop the amplification
faults here can lead to cancer

Question 6

signal transduction pathways

Answer 6

4 types of mechanism:

1. direct ligand gated channel
2. G-protein-coupled
3. tyrosine kinase-linked
4. nuclear receptor super family

Question 7

ligand gated channel

Answer 7

ion binds to receptor causing conformational change allowing influx into the cell through the channel
include:
uniporter
symporter
antiporter
ATPase dependant transport
also includes diffusion, facilitated transport and energy dependant transport

Question 8

drug resistance ATPase

Answer 8

drug enters cell via diffusion, cell activates ATPase transport to remove drug from cell

Question 9

G-protein-coupled

Answer 9

binding causes conformational shape change
can now bind to G-a subunit
triggers further change, causing dissociation of intracellular Go proteins which bind to, and cause a change to other transporter molecules
target of ~40% modern drugs

cAMP signal pathway:
messenger binds to receptor in the cellular membrane
causes change in the G-protein bound to the receptor
one sub-unit of the G-protein bins to adenylyl cyclase in the membrane
ATP arrives and is converted into cAMP

Question 10

vasopressin

Answer 10

causes antidiuresis

single amino acid mutations in V2R can cause this ability to regulate water to be lost

Question 11

tyrosine kinase-linked - Boron pg.111

includes several cytokines: IL-2,3,4,5,6 and more

Answer 11

there is a poir of receptors that hetero/homo-dimerise
GTP donates phosphate to activate intermediaries triggering a response
deficits in phosphatase will result in the ability to stop response signal being lost, since phosphate cannot be cleaved
homodimer - e.g. HER1 + HER1
very stable
heterodimer - e.g. HER1 + HER2
more unstable

Question 12

hypoxia induced factors - von hippel lindau function

Answer 12

causes angiogenesis and proliferation
protective in the case of injury
e.g. diabetic retinopathy where process is disrupted

Question 13

hypoxia induced factors - von hippel lindau function

Answer 13

causes angiogenesis and proliferation
protective in the case of injury
e.g. diabetic retinopathy where process is disrupted

Question 14

VEGF - vascular endothelial growth factor

Answer 14

inhibited by thalidomide
? therapeutic use in haematological conditions
e.g. malignancy, retinopathy

Question 15

VEGF - vascular endothelial growth factor

Answer 15

inhibited by thalidomide
? therapeutic use in haematological conditions
e.g. malignancy, retinopathy

Question 16

thromboembolism risk anti-cancer medications

Answer 16

anti-cancer drugs often affect the tumour vis indirect effects as well as direct

Question 17

TNF

Answer 17

only activates death pathways within cells in cells with oxygen
in hypoxic conditions it causes proliferation and angiogenesis leading to growth

Question 18

TNF

Answer 18

only activates death pathways within cells in cells with oxygen
in hypoxic conditions e.g. tumours, it causes proliferation and angiogenesis leading to growth

Question 19

TNF

Answer 19

only activates death pathways within cells in cells with oxygen
in hypoxic conditions e.g. tumours, it causes proliferation and angiogenesis leading to growth
if the mets are hypoxic, and the rest of the surrounding tissue is oxic, can lead to damage to surrounding tissue and proliferation of the mets

Question 20

contact inhibition

Answer 20

often lost within cancer cells

Question 21

Tyrosine kinase receptors

Answer 21

2 signalling molecule bind to 2 adjacent receptor kinase proteins
this causes them to bind together - dimerisation
these are now activated
they are phosphorylated by 6 ATP (which become 6 ADP)
they are now able to activate inactive relat proteins within the cell