Chapter 7 Flashcards
What are the components of chemical signaling pathways?
Extracellular signaling molecules, receptors, and effectors.
What are the functional categories of extracellular signaling molecules?
Neurotransmitters, hormones, and trophic factors.
What do trophic factors promote?
Growth, development, survival, and differentiation.
Where are transmembrane receptors located?
In the plasma membrane, for impermeant and some permeant molecules.
Where are intracellular receptors located?
In the cytoplasm or nucleus, for permeant molecules only.
What is an example of an intracellular signaling molecule?
Nitric oxide.
What are ionotropic receptors?
Receptors that are part of an ion channel, generating an electrical signal.
What do G proteins do?
They can activate enzymes and participate in transcriptional regulation.
What are the advantages of intracellular signaling paths?
Amplification, multiple steps/levels of control, and spatial localization.
What are the challenges of intracellular signaling?
Maintaining the signal long enough to elicit a response and controlling signaling inactivation.
What is juxtacrine signaling?
Signaling that requires cell-cell physical contact.
What is autocrine signaling?
Signaling where the molecule binds to a receptor on the releasing cell.
What is paracrine signaling?
Signaling that diffuses within the tissue of the releasing cell.
What is endocrine signaling?
Signaling where the molecule travels in the blood.
What are the types of transmembrane receptors?
Channel-linked receptors, enzyme-linked receptors, and metabotropic G-protein coupled receptors.
What activates G-protein coupled receptors?
A signaling molecule and GTP replacing GDP.
What are the types of second messengers?
Calcium ions, cyclic nucleotides (cAMP, cGMP), diacylglycerol (DAG), and inositol triphosphate (IP3).
What is the role of calcium in signaling?
It activates kinases, triggers neurotransmitter release, and binds to transcriptional activators.
How is cAMP activated?
By trimeric Gs proteins via adenylyl cyclase.
What does diacylglycerol (DAG) activate?
Protein kinase C (PKC).
What is the role of protein kinases?
They modulate the activity of enzymes, neurotransmitter receptors, ion channels, and structural proteins.
What is the function of protein phosphatases?
They dephosphorylate proteins, modulating their activity.
What is the significance of c-fos in signaling pathways?
It acts as a transcriptional activator for other genes.
What are the characteristics of mood disorders?
Prolonged mood alterations, high heritability, and shared susceptibility genes with schizophrenia.
What is the treatment focus for depression?
Biogenic amines, particularly selective serotonin reuptake inhibitors.
CamKII
- Ca2+/calmodulin dependent kinase
- autophosphorylates
- abundant in dendritic spines
What is the main importance of dendritic spines?
Growth and development
What does protein kinase C require to activate?
Both Ca and DAG
Mitogen-activated protein kinases (MAPKs)
- extracellular signal-regulated kinases (ERKs)
- activated by osmotic stress or heat
What are the challenges of intracellular signaling?
- The signal must last long enough to work.
- The signal must turn off when it’s no longer needed.
What activates pka?
cAMP
Are protein kinases or phosphotases LESS specific?
Phosphotases
What does PP1target?
- serine/threonine
- Metabolic enzymes
- K+ and CA2+ channels
- AMPA and NMDA glutamate receptors
How is PP1 inactivated?
pka phosphorylation
PP2A characteristics
- always active
- targets same as PP1
- defect associated with Alzheimer’s
What does PP2B (calcineurin) target?
- Transcriptional regulator NFAT
- Ion channels
AMPA dephosphorylation associated with long term depression in
hppocampus
How is PP2A inactivated?
- phosphorylation
- Post-translational modification
How is PP2B activated?
calcium and calmodulin binding
How long does it take for second messengers to have an effect?
30-60 minutes
What is c-fos
transcription al activator
What does CREB target/activate?
neuropeptides and c-fos
What is an example of a pathway that has a single signal with multiple responses?
Tyrosine Kinase A
Neural growth factor binds here
How are Purkinje cells in cerebellum activated for long term depression?
Need calcium from 2 sources/pathways for an effect
What are the side effects of first generation dopamine drugs?
Movement disorders (tremors, immobility)
What do depression meds target?
Treatment targets biogenic amines
What is depression?
Low mood > 2 weeks not associated with a specificcause
