Ca/calmodulin activate CaMKII by by displacing the inhibitorydomain from the catalytic site
how is PKA activated?
cAMP activates PKA by binding to the regulatory subunits and causing them to release activate catalytic subunits.
how is PKC activated?
DAG causes PKC to move from the cytosol to the plasma membrane, where it also binds Ca and phosphatidylserine, a membrane phospholipid. These events relieve autoinhibition and cause PKC to phosphorylate various protein substrates
In general, protein phosphotases display ___ substrate specificty than protein kinases
how are MAPKs activated?
by other protein kinases
true or false, CREB can be activated by a number of different signaling pathways?
what is CREB?
CREB is a ubiquitous transcriptional activator that can be activated within a signaling pathway to enhance hte transcription of a gene
what are the two ways that nuclear receptors work?
one is a signaling molecule binding to a receptor in the cytoplasm of the cell, the complex then migrates to the nucleus and binds to a specific gene, enhancing RNA polymerase affinity to that gene. Another is when a receptor is bound to DNA and serves as a potent repressor of transcription. Upon binding of the signaling molecule, the receptor changes and opens that DNA for binding by polymerase
protein kinases usually phosphorylate which amino acids?
Ser/Thr or Tyr
c-fos is considered to be a(n) _______ ____ gene
immediate early gene
how does c-fos work?
stimulation of the target cell causes c-fos to be synthesized in large amounts. Once synthesized, c-fos protein can act as a transcriptional factor and bind to other genes
the second-order genes that c-fos binds to are termed ______ _______ genes
delayed response genes
How does signaling pathway affect long-term depression in purkinje cells?
When parallel fibers (PFs) are active, they release the neurotransmitter glutamate onto the dendrites of Purkinje cells. This activates AMPA-type receptors, which are ligand gated ion channels, and causes a small EPSP that briefly depolarizes the Pirkinje cell. The glutamate released by PFs activates metabotropic glutamate receptors, which stimulates phospholipase C to produce IP3 and DAG. When the PF synapses alone are active, these intracellular signals are insufficient to open IP3 receptors or to stimulate PKC.
LTD is induced when PF synapses are activated at the same time as glutamatergic climber fiber synapses that also innervate purkinke cells. The climbing fiber synapses produce large EPSPs that strongly depolarize the membrane potential of the Purkinje cell. This depolarization allows Ca to enter the Purkinje cell via voltage-gated Ca channels. When both synapses are simultaneously avtivated, the rise in intracellular Ca concentration caused by the climbing fiber synapse enhances the sensitivity of IP3 receptors to the IP3 profuced by PF synapses and allows the IP3 receptors within the Purkinje cell to open, This releases Ca from the endoplasmic reticulum and further elevates Ca concentrations. The Ca and the IP3 can then activates PKC to commence LTD. This results in the AMPA-type receptors producing a smaller depolarization when they are activated
How does tyrosine hydroxylase phosphorylation affect catecholamine synthesis and release?
Phosphorylation of tyrosine hydroxylase results in conformational changes in the enzyme, which increase its catalytic activity. This increased synthesis in turn increases the release of catecholamines and enhances the postsynaptic response produced by the synapse
what are the two types of g proteins?
heterotrimeric and monomeric g proteins
what are the two proteins that translocate Ca to the extracellular space?
calcium pump and Na/Ca exchanger
how is Ca concentration regulated in the cytoplasm?
ATPases on the cell membrane remove Ca, Ca is pumped into endoplasmic reticulum and mitochondria, and nerve cells contain other Ca binding proteins-- such as calbidin-- that serve as Ca buffers
Which type of calcium-releasing channel have we learned about in class?
the IP3 receptor
what are the major second messengers?
Ca, DAG and IP3, and cyclic mononucleotides
how is calmodulin activated?
Typically, when are Ser/Thr kinases used and when are Tyr kinases used?
typically, second messengers activates Ser/Thr kinases and extracellular signals activates Tyr kinases
neurobio 911 ch 7 of Purve's book: molecular signaling within neurons part 1 (ACh MAPK CaMKII cel
neurobio 911 ch 7 of Purve's book: molecular signaling within neurons part 1 (ACh, MAPK, CaMKII, cell amplification, norepinephrine, purkinje cells, long term depression, tyrosine hydroxylase)