Lecture 16 - Health and Disease in Signalling Flashcards
What mechanisms can there be loss of control of signalling?
Genetic - local/isolated, mutation of a common or rare component
Disease - local/isolated - local e.g. cholera, whole body e.g. diabetes
Where can loss of control occur?
At any point of the pathway
How can loss of control occur at the receptor level of GPCR?
Over-production of messenger/ligand
Under-production or inactive messenger
Failure of receptor to recognise ligand
Failure of receptor to activate G-protein
Failure of receptor to deactivate or always active
What are responsible for forming the core of the GPCR?
The transmembrane domains
What part of the GPCR interacts with the G-protein?
Cytoloops 2 and 3 and the C-terminal
What part of the GPCR interacts with the ligand?
N-terminal, exoloops and the core
Example how rhodopsin works?
It is a GPCR
It already has its agents attached
Light comes in and causes the G-protein to be activated
How is retinal to lysine?
Retinal is attached at TM7 to lysine
What do the surrounding amino acids of the lysine dictate?
The absorbance of the chromophore, they determine the colour of light this receptor can detect
Why are males mainly affected with colour blindness?
Because the genes for red and green are located on the X chromosome, around 2% of X chromosomes only have one ‘colour’ gene
What does a defect in G-alpha-12 cause?
Platelet dysfunction
What does a defect in G-alpha-t cause?
Night blindness
What does a defect in G-alphas cause?
McCune Albright syndrome
What does a defect in G-beta-3 cause?
Hypertension
What does a defect in G-alpha-i2 cause?
Adrenal cortical tumour
