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141 Cards in this Set
- Front
- Back
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Fill in the blanks....
Upsteam cell ----> ____________ The sender----> ____________ the inducer----> ____________ |
---->downstream cell
---->The receiver ---->the responder |
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signalling transduction pathway is also called
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intracellular signalling pathway, or secondary messenger cascade
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signals induce ________ ______
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effector fxns
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What is the kind of specialized kind of paracrine system where the signalling cell is also the target cell?
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autocrine
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What is paracrine signalling?
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local, short distance signalling
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Which molecules are typically used in cytosolic exchange signalling?
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ions
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Which two types of signalling do not require a receptor?
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cystosolic exchange and juxtacrine signalling
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What is juxtacrine signalling?
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signalling by cellular adhesion
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Where are receptors found?
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In the PLASMA MEMBRANE 90% of the time
(or in the ECM, or soluble in cytosol, ER, nuclear membrane) |
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Signals are polar because
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if they were non-polar, they would diffuse across the membrane (if small enough)
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Which signals are non-polar?
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Horomones
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Ampipathic means....
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mostly non-polar, but a tiny bit polar residue
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Ampipathic cells must be transported how?
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through the blood
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Horomone receptors are found?
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in the cytosol
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hormones bind to the _____ ______ to regulate transciption
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transcription factor
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In plants, gap junction is used for what kind of signalling?
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cytosolic exchange
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How are ions used as signals?
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They are cofactors for enzymes
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Hormones use what kind of signalling?
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Endocrine
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Neurons use what kind of signalling?
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Paracrine
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Juxta- means what?
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next to
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In juxtacrine signalling, the target and the signal cells have to ______
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touch
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In juxtacrine signalling, the target has to travel to the ______
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signalling molecule
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Contact dependance is a trait of which kind of signalling?
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juxtacrine signalling
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Receptors that are membrane bound are ALWAYS_______ _________ ______
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trans membrane proteins
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most signals are hydro______
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philic
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Ion channel-linked receptors are?
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Gated ion channels
ion channels that are receptors |
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Gated ion channels are normally closed but told to open when ____________
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they receive a signal, once they are open, ions are free to travel
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Integration means
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thousands of signals, but you can only do one thing. You integrate that signal
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Modulate means
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To turn on or off or cause conformational changes
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Most signal transduction pathways lead to_______
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gene expression
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Hard-wiring is?
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When cells are connected, allowing speed of signal transduction
1-2-3-4-5...boom boom boom |
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Give an example of a molecular switch, or relay...
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Phosphorylation
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A G protein is _______ when a GTP is bound to it and is _________ when a GDP is bound to it.
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active with GTP, inactive with GDP
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A cell won't do anything unless.....
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it is told to do so
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For a cell to die it need to be told 2 things...
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Needs to be told to die AND be told not to Live
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G-protein linked receptors have what on each side of the membrane?
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Cytosolic side: G-protein
Non-cytosolic side: receptor |
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Two super groups of G-proteins are called?
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Trimeric and monomeric
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Any G-protein linked to a receptor is a g-protein from which group?
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Trimeric g-protein
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Half of pharmecutical drugs target what?
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G-protein linked receptors
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GTP+ hydrolysis =?
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GDP
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the effector protein is the ____
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goal
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Cyclic AMP is a type of _____ _____
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second messenger
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pka =
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protein kinase A
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How is PKA normally found?
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as a tetramer
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PKA binds to what?
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cyclic AMP
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when PKA is bound to regulatory subunits, it is______
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inactive
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when PKA binds to cAMP, what happens?
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PKA becomes active
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Where does PKA activity occur?
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cytosol
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where does PKA go once its activated?
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In the nucleus thru a nuclear pore.
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once PKA goes into the nucleus, it signals which protein?
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CREB
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When CREB is phosphorylated by _____, what happens?
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by PKA, it regulates gene expression (turns on gene in this case)
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a protein that uses the ampification method?
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cAMP
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How do you control the amount of signalling protein produced?
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By increasing the longeivty of the original signal
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Phospholipase C is a _______ protein
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peripheral
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in the Phospholipase C pathway, PIP2 breaks into ____ and ____
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DAG and IP3
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DAG is composed of?
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glycerol+ a fatty acid
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DAG is attached to...
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the plasma membrane (cytosolic side)
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Divergent cross-talk is?
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when both pathways must occur (both IP3 and DAG must be made for the pathway to work)
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Phosphotidyl Insolital is also known as
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PIP2
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What does IP3 do?
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Activate a Ca ion channel (either in the ER or the plasma membrane)
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pkC aka ______
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Protein kinase C
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pkC requires what?
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CA+ ions
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DAG recruits which protein to the membrane?
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pkC
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Example of convergent cross-talk?
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When DAG pulled pkC toward the membrane and Ca+ ions come from IP3 opening the ion channel. These two steps come together to activate pkC
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Enzyme-linked receptor example
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Receptor tyrosine kinase
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In Enzyme-linked receptors, the receptor is also a ______
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enzyme
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In animals ______ ______ are the most common enzyme-linked receptors
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tyrosine kinases
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the signalling molecules of tyrosine kinase form a ______
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homodimer
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tyrosine kinase is two identical molecules that do not do what?
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Touch each other
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An unphosphorylated RTK dimer is activated/inactivated?
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inactivated
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auto-phosphorylation
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when the RTK dimer phosphorylates itself
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the unphosphorylated RTK dimer catalyzes ______
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auto-phosphorylation
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The phosphorylated RTK dimer catalyzes ______
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other enzymes
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The phosphorylated RTK dimer acts as a _____ protein
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scaffolding
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The phosphorylated RTK dimer acting as a scaffolding protein is an example of both _____ and____
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scaffolding and hard-wiring
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PLC can be activated by EITHER one signal OR another signal. This is an example of
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convergent crosstalk
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RAS is a _______ ______
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monomeric G-protein
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GEF is a _______ that does what? what pathway
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enzyme, that exchanges GDP for GTP (RAS pathway)
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GEF is pulled up to the membane by ______ to get near the RAS protein
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an adaptor protein
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the phosphorylated RTK receptor recruits ______ which is also attached to ______
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the adaptor protein (grb2), GEF
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MAP kinase cascade is....
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MAP kinase kinase kinase --->MAP kinase kinase-->MAP kinase
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Most MAP kinases regulate _______ ______
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transcription factors (which leads to regulation of gene expression
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Each RAS activating a # of MAP kinase kinase is an example of _____ crosstalk
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divergent
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Each MAP kinase kinase kinase being able to activate a # of MAP kinase kinases, is an example of _____ crosstalk and also ______
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divergent, amplifation
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More steps in a pathway means a greater chance for _____ and _____ crosstalk
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amplification, divergent
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Are all enzyme-linked receptors, enzymes themselves?
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No, some are enzymes and some are just linked to enzymes
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heterodimer is?
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a dimer formed of two DIFFERENT subunits
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What is the importance of heterodimers?
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It allows variation
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Plants do not have a ______ system, they instead have a ______ system
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endocrine, paracrine
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Plants have _____ factors and ______ used in signalling
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growth factors, hormones
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In plant cells, signal transduction pathways usually _______ gene expression
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inhibit
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Does a ligand have a long or short life?
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Short (the cell doesnt need to be told more than once what to do)
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Name two ways to regulate ligand-receptor interactions?
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Decrease the amount of ligand available, or decrease the amount of receptors available
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Name three ways to regulate whether or not a receptor is there
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desensitization, downregulation and negetive feedback
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If a receptor has a high/low affinity, then it needs more/less ligand
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high affinity needs less ligand, and low affinity needs more ligand
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What is desensitization?
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When a receptor protein has a protein attached that prevents it from recognizing the ligand, therefore making it useless (desensitized)
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Downregulation is?
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The cell might make the receptor, but its then degraded (without being replaced)
reducing the amount of receptor |
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Negetive Feedback is?
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The receptor is blocked by the product of its own pathway. Feedback loop. (ex: Receptor makes A, and A blocks the receptor when enough A is made)
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Convergent cross talk is for _______ priority pathways
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high
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Glycogen breakdown is stimulated by either _____ or _____ which is an example of _____ crosstalk
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glucagon, vasopressin, convergent
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divergent crosstalk relies on _____ _____
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hard wiring
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Programmed cell death requires _____#____ signals
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1 signal
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Is multiple inputs sometimes required?
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yes
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name an example of multiple inputs-
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T cell activation
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All 3 types of muscle cells require _____ and myosin filaments
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microfilaments
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In muscle cells, ______ is required in the cytosol for contraction. Contraction is also called the ____ ____
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Ca+, power stroke
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Muscles require ______ to relax
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ATP
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Contraction occurs when a _____ head binds to a _____
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myosin , microfilament
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all or nothing contraction occurs which which types of muscle cells?
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skeletal and cardiac
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For all or nothing muscle contactions, a large amount of ____ is needed
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Ca+
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Which cells are contracted laterally and which radially?
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smooth muscle cells are contracted radially and striated (skeletal and cardiac) contract laterally
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____ muscle is voluntary
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skeletal
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Skeletal muscle performs at a ____ cost with _______ fatiguablility
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High cost with high fatiguability
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syncition?
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multiple pieces working in unison
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Skeletal muscle get fatigued by a lack of _____ ions
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Ca
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DHP receptor in the T-tubule is/is not directly linked to a Ca ion channel (regarding skeletal muscle
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is not
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The Ryanodine receptor on skeletal muscle is/is not a Ca+ channel
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is
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skeltal muscles are _____ _____ ____
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all or nothing
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is cardiac muscle all-or-nothing or graded contraction?
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all-or-nothing
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In _____ cells, the DHP receptor is linked to a calcium ion channel
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cardiac
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Main source of calcium ion for cardiac muscles is from the ____
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ECM
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Smooth muscle cells get Ca from both the _____ and the _____
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cytoplasmic reticulum, and the ECM
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Caldesmon is found in _____ cells
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smooth muscle
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When caldesmon is degreaded, what is exposed?
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actin binding sites
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the graded contraction of smooth muscle cells is affected by...
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the amount of Ca in the cytosol and the # of myosin binding sites exposed
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motility= ______ _____
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cell movement
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Swimming requires ____ or ____
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cilia or flagella
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prokaryotic cells use cilia/flagella
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flagella
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flagellum is composed of the protein _____
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flagellin
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when the flagellum turns clock-wise it _____
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tumbles
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when the flagellum turns counter clock-wise it _____
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straight swims
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In cilia and flagella, what is the role of dynein?
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anchored onto the microtube and bends and pulls to create whipping effect
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Cilia can be used for swimming and _____
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eating
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Which 2 kinases are required for crawlin?
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Rac and Rho (rock n roll!)
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rac and rho (which one is at leading edge which is at lagging edge?)
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rac=leading
rho=lagging |
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Chemoattractants do what?
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signal for crawling
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Polymerization of microfilaments causes
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crawling
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Cofilin removes the___ ____ ____from the negetive end.
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ADP bound actin
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microfilaments is an anchor for _____
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integrin
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nastic movements are
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non-directional responses to stimuli
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Tropic movement
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growth or turning in response to enviromental stimulus
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