Cytokine receptors, T cell receptors, integrins, TGF-beta receptors Flashcards
What are 3 examples of tyrosine kinase associated receptors?
Integrins, T cell receptors and cytokine and hormone receptors
What is an example of receptor ser/thr kinase?
Transforming growth factor beta-signalling
What are cytokines?
Secreted mainly by immune cells and modulate the immune response
What are chemokines?
Subset of cytokines that act as chemoattractants
What are hormones?
Produced by endocrine glands and distributed by the bloodstream. Can be small organic molecules, peptides or proteins.
What are growth factors?
Stimulate cell growth, proliferation and differentiation. Some cytokines and hormones act as growth factors.
What do cytokines and hormones activate?
The JAK-STAT pathway
What is JAK?
Janus kinase - contains 2 tyrosine kinase domains (only one is active)
What is STAT?
Signal transducer and activator of transcription
Why is the JAK-STAT pathway simpler than the MAP kinase pathway?
It only contains one intermediate so less scope for regulation
What does a cytotoxic T cell do?
Recognises tumour cells. Punches holes in toxic cells and destroys
How do T cells recognise foreign antigens?
Antigens are presented my MHC proteins. Cytotoxic T cell and class I MHC. Helper T cell and class II MHC.
What does MHC stand for?
Major histocompatibility complex
Where do the antigens that MHC class II proteins originate from?
Endocytosis of foreign proteins
Where do the antigens that MHC class I proteins originate from?
Proteasomal degradation of cytosolic proteins (self and foreign)
Which co-receptor does Tc have?
CD8 (binds to MHC class I)
Which co-receptors does Th have?
CD4 (binds to MHC class II)
What are non-receptor tyrosine kinases?
Cytoplasmic enzymes that are responsible for catalysing transfer of phosphate group from nucleoside triphosphate donor (eg. ATP), to tyrosine residues in proteins.
What is Lck and what does it react with?
A Src family kinase that gets activated by binding of TCR and co-receptor to a peptide-MHC complex (non-covalent)
What do integrins do?
Link ECM to cytoskeleton
What happens when integrin is activated?
Alpha and beta domain separates, stretched out (inside has strong talin binding, outside has strong ligand binding)
What does FAK stand for?
Focal adhesion kinase
What do TGFB do?
Inhibit cell growth - many tumours have mutations in TGFB pathway
How is TGFB produced?
As an in active precursor stored in the ECM
