Cell-Signaling Study Guide Flashcards
(28 cards)
What are the 4 types of cell signaling and give an example?
Direct cell-cell signaling
- Delta Notch
Endocrine
- Adrenaline, insulin, steroid
Paracrine
- Neurotransmitter
Autocrine
- Immune Response
What are the functions of Acetylcholine in heart muscle, salivary gland, and skeletal muscle, and how? What channel?
Decreased Frequency of Contraction
Secretion of Saliva
Contraction
Neurotransmitter
Two types of signaling molecules: What are they?
Large or Hydrophilic
-Can’t cross membrane
-binds to cell surface receptors
-majority
Small or Hydrophobic
-Diffuses across membrane
-Binds to receptors inside cell
-Only a few molecules
Nuclear Receptors of Steroid hormone (Testosterone, estrogen, progesterone Glucocorticoids Mineralosteoids) and non-steroid hormones (Thyroid hormone Vitamin D3 Retinoic acid) are transcription factors that bind DNA, therefore regulate gene expression
Nuclear Receptors of Steroid hormone (Testosterone, estrogen, progesterone Glucocorticoids Mineralosteoids) and non-steroid hormones (Thyroid hormone Vitamin D3 Retinoic acid) are transcription factors that bind DNA, therefore regulate gene expression
Signaling pathway of glucocorticoid
Stimulate Glucose Production
NO enters smooth muscle cell and reacts with iron in the active site of the guanylyl cyclase, which increases cGMP level and cause blood vessels to dilate
NO enters smooth muscle cell and reacts with iron in the active site of the guanylyl cyclase, which increases cGMP level and cause blood vessels to dilate
NO is paracrine signal: acts local, short half life, it is rapidly converted to nitrates and nitrites
NO is paracrine signal: acts local, short half life, it is rapidly converted to nitrates and nitrites
NO synthesized from arginine
NO synthesized from arginine
Neurotransmitters bind to membrane receptor: ligand gated channel and G-protein coupled receptors.
Neurotransmitters bind to membrane receptor: ligand gated channel and G-protein coupled receptors.
PDGF signaling plays an important role in wound healing
PDGF signaling plays an important role in wound healing
Aspirin inhibits the synthesis of prostaglandin by inhibiting enzyme COX, therefore reduces Blood platelet aggregation, inflammation, and smooth muscle contraction.
Aspirin inhibits the synthesis of prostaglandin by inhibiting enzyme COX, therefore reduces Blood platelet aggregation, inflammation, and smooth muscle contraction.
G-protein-linked receptors activates G proteins, G protein targets ion channels or membrane bound enzymes
- Upon receptor activation, Heterotrimeric G protein separates into α and βγ subunits,
- GTP bound G Alpha subunit is active, which can activate target protein adenylate cyclase to increase cAMP level, cAMP binds to the regulatory submit of protein kinase A to activate protein kinase A
- It can also active another target protein phospholipase C which split PIP2 to IP3 and DAG, IP3 opens Ca2+ channel in ER. Diacylglycerol and calcium activate protein kinase C
The major function of cAMP in animal cells is to
activate protein kinase A
How protein kinase A is activated?
adenylate cyclase -> cyclic AMP -> kinase A
How protein kinase A activates genes?
Binding cAMP to its regulatory subunits, release its catalytic subunits, enter nucleus and phosphorylate CREB, a transcription factor
How protein kinase A regulates glycogen metabolism?
Phosphorylates phosphorylase kinase and
glycogen synthase
Cholera toxin modifies the a subunit of a G protein so that it cannot hydrolyze its bound GTP, and increased Gαs activation leads to increased adenylate cyclase activity
Cholera toxin modifies the a subunit of a G protein so that it cannot hydrolyze its bound GTP, and increased Gαs activation leads to increased adenylate cyclase activity
The second messenger for signal transduction in the eye is _____
cGMP
Receptor tyrosine kinase is the most common enzyme linked receptor. Most growth factor receptors are protein tyrosine kinases. The steps of growth factor signaling:
- Signal molecule binding induces dimerization of the receptor
- Activated receptor tyrosine kinases phosphorylate themselves
- Triggers assembly of intracellular signaling complex on receptor tails
Ras, a small membrane bound monomeric G protein, is activated by many receptor tyrosine kinases. GTP bound ras is active and GDP bound is inactive
Ras, a small membrane bound monomeric G protein, is activated by many receptor tyrosine kinases. GTP bound ras is active and GDP bound is inactive
MAP kinase (mitogen activated kinase) pathway: ras –raf-mek-erk- gene expression ; Scaffold proteins organize signaling components into functional groups
MAP kinase (mitogen activated kinase) pathway: ras –raf-mek-erk- gene expression ; Scaffold proteins organize signaling components into functional groups
Second messengers we discussed:
cAMP, cGMP, IP3, Ca++
Ca++ binds to Calmodulin to activate
calmodulin) kinase II and Myosin Light Chain Kinase (MLCK).
How TGF-β signaling works:
TGFβ receptors phosphorylates Smad
