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Overview of Cell Signalling

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imissyou419's version from 2016-12-17 05:03

Section

Question Answer
Endocrine signallingacts on a far away organ via hormones released into bloodstream, slow
Paracrine signallingacts on a nearby target via NT & cytokines (local mediators), PDGF/FGF
Autocrine signallingacts on itself via growth factors
Synaptic signallingpre to post synaptic nerves via NT; long distance communication, fast
Adrenaline (released from? type of hormone? effect?)released from adrenal gland, tyrosine derivative, increase BP, HR, metabolism
Cortisol (released from? type of hormone? effect?)released from adrenal gland, steroid, affects metabolism of proteins, carbs, lipids
Estradiol (released from? type of hormone? effect?)released from ovary, steroid, induces and maintains secondary female sexual characteristics
Insulin (released from? type of hormone? effect?)released from pancreatic beta cells, protein, increase glucose uptake, protein, lipid synthesis
Examples of paracrine signalling molecules and what they doPDGF - wound healing; FGF - cell growth & differentiation
Examples of autocrine signalling moleculescytokine interleukin-1 in monocytes, VEGF in cancer cells promoting angiogenesis
Type I diabetes cause and treatment Pancreatic beta cells are lost, therefore no insulin production -> blood sugar levels accumulate to toxic levels. Treatment: inject insulin
Type II diabetes cause and treatment cells do not respond to insulin that is produced -> blood sugar levels accumulate to toxic levels. Treatment: healthy eating, regular exercise, exogeneous insulin, blood sugar monitoring, metformin (suppress glucose production by liver so increase sensitivity of cells to insulin)
There are many types of receptors and effectors but not many types of secondary messengers why?the concentration of secondary messengers fine tunes the response (activate or inactivate pathway)
T/F - a single ligand when acting on the same receptor will produce the same response in 2 different cells?F - a single ligand can produce different responses on different target cells because of different intracellular machinery; a single ligand can produce different physiological effects on different receptors too; SIGNALLING OUTCOME DEPENDS ON CONTEXT
Type I receptors function and examplesreside in the cytosol and translocate to the nucleus; e.g. cortisol, estrogen, progesterone, vitamin D receptors
Type II receptors function and examplesreside in the nucleus as heterodimer; e.g. thyroid receptor, retinoic acid receptor
Ion channel-linked receptor examplesnAchR (Ach binds and get muscle contractility) and NMDAR (glutamate and NMDA binds to regulate neuron transmission)
EGFR functionstimulate cell survival, growth, proliferation, or differentiation of various cell types (epithelial cell); acts as inductive signal in development (epithelial cell induce other cells to become epithelial cells)
Insulin receptor functionstimulate carbohydrate utilization and protein synthesis
PDGFR functionstimulate survival, growth, proliferation, migration of various cell types
VEGFR functionstimulate angiogenesis
FGFR functionstimulate proliferation of various cell types (wound healing); inhibit differentiation of some precursor cells (fibroblast), acts as inductive signal in development (fibroblasts induce differentiation)
TGFbeta (what kind of receptor, function)Receptor serine/threonine kinase; A) binding of TGFbeta causes type II receptor to phosphorylate type I receptor. B) phosphorylated type I receptor recruits and phosphorylates SMAD 2 or SMAD3. C) Phosphorylated SMAD2 or SMAD3 dissociate from receptor and oligomerizes with SMAD4. D) SMAD2/3-SMAD4 oligomer translocates to the nucleus, recruit other gene regulatory proteins and activate transcription of specific target genes
TGFbeta biological rolesdevelopment, adult - (tissue repair, immune function, many other processes), cell proliferation, cell differentiation, ECM production, cell death (in cancer it is a growth promoter)
Examples of GEFGPCR, Sos (Ras-GEF)
Examples of GAPRGS
Serine/Threonine protein kinase examplesPKA, PKC, MAPK, GRKs, mTOR (central regulator of cell metabolism, growth, proliferation, survival)
PKA consensus sequenceArg-Arg-X-Ser/Thr
Tyrosine consensus sequenceAsn-Pro-X-Tyr
Tyrosine kinase receptor examplesEGFR, FGFR, PDGFR
Non-receptor tyrosine kinase exampleSrc
Explain Myocardial infarctionincreased PKC expression which results in increased troponin phosphorylation, which results in decreased contractility (systolic dysfunction); high blood troponin levels indicate cardiac muscle cell death
T/F - phosphorylation of a protein means it's turning it onF - phosphorylation could be turning a protein on or off
T/F - protein A is inhibitory in cell A, protein A must also be inhibitory in cell BF - something that is inhibitory in 1 context may not be inhibitory in another (TGFbeta is inhibits growth under normal conditions/in early stages of cancer, TGFbeta promotes growth & tumorigenesis as cancer progresses)
Signal integration Protein is only activated when both sites are phosphorylated i.e. activated when signals A & B are simultaneously present (for fine-tuning of signals)
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