Created by J yadonknow
over 6 years ago
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Question | Answer |
Intercellular communcation | Para/auto/endo/juxtacrine |
Paracrine | Signal affects close prox. cells Lim travel |
Autocrine | Sender+target same cell type of paracrine |
Endocrine | Usually acts on distant cells can affect nearby hormones |
Juxtacrine | Signalling cell in direct contact / target cell Gap junction connexons OR signalling protein on cell surface one cell physically interacts w/ receptor of other |
Cell influence response | 1) Reg its R # 2) Synth. dif. isoforms of R 3) Most ligands are hydrophilic, can't pass through LBL, don't cause a response. |
Cell signalling for cell surface R's (9) | 1. Pack+synth of sig mol. into IC vesicles. 2. Release into EC space by exo 3. Transport to R 4. Binding of sig to spec. cell surf R, induces conf. Δ+ activation. 5. +R then + dwnstream sig transduct. pro/2' mess. 6. Leads to + of E protein(s) 7a. Short-term Δ 7b. Long-term Δ (gene expression) 8. Term of response by - FDBCK from IC sig mol. 9. Removal of EC signal |
Modification of proteins for signal transduction | Protein cov. mod by +Pi +Pi usually induces confo Δ +Pi added from ATP by PK -Pi by phosphatase |
How is this tightly regulated? | Opportunity to amplify/regulate and control pathway at every level |
Termination of Signal (3) | Eliminate EC ligand Deactivate signal transduction proteins Remove +R from PCM via Endocytosis |
Eliminate EC ligand | enzymatic degradation |
Deactivate signal transduction proteins | -Pi by phosphatases |
Remove +R from PCM via Endocytosis | R+L internalised Either: Seperated, R recycled, L destroyed OR: Both destroyed |
Natural endogenous kinases (3) | Hormones Cytokines Growth Factor |
Epinephrine/histamine are | Small H2O soluble molecules |
Prostaglandins are | lipophilic molecules |
Glucagon and insulin are | H2O soluble peptide hormones |
Hormones detected by IC R | Lipophobic like steroids |
Cytokines are | Peptides of varying sizes |
3 Examples IITNF | e.g. Interleukins/interferons/tumour necrosis factor |
What's their function | Co-ordination of the immune system |
Growth factors are | Peptides of varying sizes |
What type of signalling do they employ? | Para/autocrine signalling |
What's their function? | Regulates growth+differentiation |
Agonist | Bind and + R, inducing signal + bioresponse |
Antagonists | Binds R, doesn't induce signalling |
Degrees of agonist action | Full/partial leads to full/partial activation |
Factors of drug action (2) | Affinity Intrinsic action |
What is affinity? | ability of drug to bind to specific R |
What is their intrinsic action? | inherent ability to induce bio signalling |
What does a value of 1 mean? | 1= how well natural ligand works, the benchmark |
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