Glycerophospholipid metabolism
Terms
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- glycerophospholipids consist of?
- A glycerol back bone, two fatty acid chains, and a phosphate head group that is variable and denotes the name.
- Phosphatidic Acid
- gycerophospholipid w/ no head group
- Phosphatidylcholine
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AKA Lethicin
need for surfactant production
If lacking RDS-- as in premature infant
Deficiency also results in dermatitis in TPN patients - Phosphatidylinositol
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cleaved to form IP3 & DAG
Important in signal transduction
MOA of lithium
Arachadonic acid -
Degradation of Glycerophospholipids:
Phospholipase A2
What does it cut and why( what is the product) ? - Phosphatidylinositol, to release arachadonic acid which is the precursor for prostaglandins
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Degradation of Glycerophospholipids:
Phospholipase A2
Where and when does it cut?
What is it inhibited by -
It is present in pancreatic secretions and snake and bee venom.
It requires trypsin and bile salts for activation.
It is inhibited by glucocorticoids (cortisol) -
Degradation of Glycerophospholipids:
Phospholipase C
What does it cut and why( what is the product) ? - Phosphatidylinositol. It is activated by PIP2 system to release second messangers--IP3 & DAG.
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Degradation of Glycerophospholipids:
Phospholipase C
Where and when does it cut? - Found in liver lysosomes and alpha toxins of bacteria.
- Describe steps of degredation of Phoshatidylinositol by Phospholipase C
- Hormone meets receptor. Receptor interacts with G protein. G protein activates Phospholipase C. Phospholipase C cleaves Phoshatidylinositol to IP3 & DAG. IP3 activates Ca++ channel which activates protein kinases. Kinases activate phosphorilations which mediate cellular response.
- MOA of Lithium
- IP3 needs to be recycled. This pathway is blocked by Lithium