Cytokines produce the signals for receptors to pick up and recognise - eventually alters transcription
Travel in the bloodstream
What are the 4 structural families?
TNF - Tumour necrosis factor
Interferons
Chemokines
Hematopoeitin
What is the structure of a Tumour necrosis factor (TNF)?
Beta strand structure
It is a ligandtrimeric receptor
What is the structure of interferons?
The cytokine is alpha helical
The interferon receptors are beta stranded
What is the structure of chemokines?
Small
Beta-alpha fold - different folds cause different functions and structures
What is the structure and role of EPO hematopoeitin?
Alpha helical structure
The receptors are beta stranded - 2:1 ratio of receptors to EPO molecule
The EPO molecule brings the receptors together - makes more blood cells
What does the cytokine response depend on?
the expression of a cognate/associated receptor
the cell type and development - chromatin structure, constellation of transcription factors (different receptors presented on cell surface) and developmentalhistory
When is EPO produced?
When the body needs more red blood cells for storing oxygen - eg in high altitudes
What is Hif?
Hypoxia inducible factor - transcription factor
Can detect low levels of oxygen - hypoxia
What is the role of Hif?
In hypoxic conditions - asparaginehydroxylasehydroxylatesasparagine amino acids on Hif1-alpha and stabilises it
Hif1-alpha translocates to the nucleus and promotes EPO production.
In normal oxygen level conditions - prolyl hydroxylasehydroxylatesproline amino acids on Hif1-alpha
Marks it for ubiquitylation and destruction - noEPO production
What does EPO stand for?
Erythropoietin
What does EPO do?
EPO is a cytokine and stimulates red blood cellmaturation