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24 Cards in this Set
- Front
- Back
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What is contact dependent signaling?
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The signal cell must be in close contact with the target cell. The signal is membrane bound.
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What is paracrine signaling?
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Signal cell is nearby target cell.
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What is neurocrine (synaptic) signaling?
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A specialized form of paracrine signaling. Nerve cell dumps neurotransmitter into synapse close to target cell. (fast)
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What is endocrine signaling?
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Signal molecule travels a far distance to the target cell. (slow)
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What is autocrine signaling?
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The signal molecule binds to a receptor on the same cell or identical cells.
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Cardiac muscle and skeletal muscle react differently to acetylcholine. This is an example of the idea that..
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A single signal molecule may bind to different receptors on two different target cells.
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Acetylcholine binds to the same receptor in the salivary glands and cardiac muscle cells but elicits different response. This is an example of the idea that...
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Same signal molecule binds to the same receptors of different cells and promotes different responses because of differences in intracellular signaling components
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What is desensitization?
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A form of negative feedback where the target cell loses the ability to respond to a signal in the continued presence of the signal.
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What are 5 ways thats desensitization can occur?
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1) Receptor sequestration
2) Receptor down regulation 3) Receptor inactivation 4) Inactivation of intracellular signaling proteins 5) Production of inhibitor proteins |
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What is a scaffold protein?
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They bring two or more signaling proteins together so that those proteins can interact more quickly and efficiently and so that the signal is directed down one specific route.
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What 3 general functions do signaling proteins have?
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They can relay, transduce, amplify, integrate, spread, anchor, modulate
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What is a importance of second messengers such as IP3, cAMP and Ca++?
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They are important, because they can be amplified in concentration and rapidly increase the signaling response downstream to distant parts of the cell.
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What are the 3 cell surface receptors?
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Ion channels
GPCR Enzyme linked receptors |
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This protein ultimately provides the activity that affect's the cell's behavior in response to the signal.
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The effector protein
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Name 3 methods that cells use to change the function of a signal protein.
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Changes in the levels of proteins by regulation of transcription, translation, degradation.
Changes in the sub-cellular location of a signaling protein Changes in protein activity |
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What is a very common intracellular method of regulation?
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"Molecular switching" utilizing phosphorylation by GTP binding protein.
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Protein kinases =
Protein phosphatases = |
transfer a phosphate from ATP to a signaling protein
remove phosphates from proteins |
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What is a key difference between protein phosphorylation and G proteins (GTP binding proteins)?
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Protein phosphorylation occurs via ATP. G proteins are molecular switches that function via GTP binding and GTP hydrolysis. G proteins do not transfer a phosphate to another protein. When the G protein is bound to GTP, it changes conformation and propagates the signal downstream.
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How many times do GPCR's tranverse the membrane?
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7 times
aka serpentine aka heptahelical |
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Name 3 methods that cells use to change the function of a signal protein.
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Changes in the levels of proteins by regulation of transcription, translation, degradation.
Changes in the sub-cellular location of a signaling protein Changes in protein activity |
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What is a very common intracellular method of regulation?
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"Molecular switching" utilizing phosphorylation by GTP binding protein.
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Protein kinases =
Protein phosphatases = |
transfer a phosphate from ATP to a signaling protein
remove phosphates from proteins |
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What is a key difference between protein phosphorylation and G proteins (GTP binding proteins)?
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Protein phosphorylation occurs via ATP. G proteins are molecular switches that function via GTP binding and GTP hydrolysis. G proteins do not transfer a phosphate to another protein. When the G protein is bound to GTP, it changes conformation and propagates the signal downstream.
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How many times do GPCR's tranverse the membrane?
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7 times
aka serpentine aka heptahelical |
