signalling

Question 1

describe signalling via second messengers

Answer 1

used by most cell surface receptors
system in which receptor activation modulates activity of an effector in the cell, usually an enzyme(can be an ion channel)

Question 2

describe signaling via receptor kinases and give an example

Answer 2

example = insulin receptor
binding of insulin causes autophosphorylation of intracellular tyrosine residues, multiple adapter proteins are then recruited that stimulate response in cell

Question 3

describe what a nuclear receptor is

Answer 3

nuclear receptors = ligand-gated transcription factors

Question 4

describe the 8 steps involved in the nuclear receptor pathway

Answer 4

for example using steroid hormones
1- enter cells by diffusion across plasma membrane
2- within cell they combine with an intracellular receptor
3- producing dissociation of inhibitory HSP proteins
4- the receptor steroid complex moves to the nucleus
5- the transcription of specific genes is either switched on or off
6- this alters mRNA levels and the rate of synthesis of mediator