Lipids as biosignaling Flashcards
glycerophospholipids are precursors of what
inositol- phosphates
what does Phospholipase C (activates by an extracellular enzyme) to the phosphotylinositol 4,5-biphosphate
it will hydrolyze it and IP3 (inositol 1,4,5-triphosphate) and DAG (diacylglycerol) are create
what does PI3Kinase to the phosphotylinositol 4,5-biphosphate
it phosphorylates it and PIP3 is create
what do ceramide and sphingomyelin
ceramide acts as a lipids rafts
sphingomyelin insulate nerve axons
eicosanoids are paracrine factors, what is it
paracrine hormones: substances that act only on cells near the point of hormone synthesis instead of being transported in the bloodto act on cells in other tissues or organs
basic precursor of eicosanoids
arachidonate, which is released from glycerophospholipids (phospholipase A2)
3 eicosanoids
prostaglandins, thormboxanes, leukotrienne
role of prostaglandins (3)
smooth muscle contraction
regulate blood flow
regulate body temperature
role of thromboxanes (2) + where they come from
they come from platelets
form blood clot and reducing blood flow
what are NSAIDs + 2 examples
they inhibit cycloxigenase enzyme (COX1 and 2), it is the enzyme in the beginning of the arachidonate (the enzyme prostaglandin H2 synthase) which catalyze an early step in the patway from arachidonate to prostaglandins or thromboxanes
- ex: aspirin and ibuprofen/
what is the role of leukotrienes
airway smooth muscle contraction
consequence of a too high concentration of leukotrienes
ot blocks the muscle contraction (that’s why we have difficulty to breath, cause ashtma and anaphylactic shock)
what do prednisone
it inhibits phospholipase 2, thus used in Ashtma, Arthrisis, Organ Transplantation…
eicosanoids are whcich type of receptor
GPCR proteins
5 signaling molecules
- Hormone: any biomolecule or chemical that elicits a cellular response by sending out a signal, acts far away from the site of its release
- Paracrine: any signaling molecule or hormone that signals any to nearby cells, no to far away cells
- Autocrine: any signaling molecule that acts on the cell that produced it
- Juxtacrine: any signaling molecule, the ligand that is produced by a cell and acts only on the immediately adjacent cell that has the receptor for this ligand
** both the ligand and the receptor must be cell membrane proteins
Pheromene: any volatile substance produced in the individual that signals to another individual
types of signaling molecules (3)
Amino acids (ex: neurotransmetteurs)
Proteins (ex: insulin)
Lipids (ex: testosterone)
4 sterol lipids + type of receptor
** all derived from cholesterol
testosterone, estradiol, cortisol, aldosterole
** nuclear receptors
precursor of Vitamin D
7-dehydrocholesterol
what happens from 7-dehydrocholesterol to 1a,25-dihydrovitamin D3 (calcitrol)
- there is a phytochemical reaction between the UV component of sunlight and the 7-dehydrocholesterol and it will create vitamin D3 (or cholecalciferol) which is inactive
- it will be convert by enzymes in the liver and kidney into 1a,25-dihydroxyvitamin D3 (calcitriol)
what do calcitriol (1a,25-dihydroxyvitamin D3)
regulates calcium uptake in the intestine and calcium levels in kidney and bone
so Ca absorption (intestine), Ca exctretion (kidney), Ca storage (bone)
the precursor of Vit A and its 2 derivative
precursor: B-carotene
derivatice:
1. retinoic acid: hormonal signal (change in gene expression)
2. retinal: neuronal signal (vision)
nuclear receptor of vitamin A
retonoic acid receptor (RAR) ; retinoid X receptor (RXR)
7 tocopherols (any several forms of Vitamin E)
vitamin E Vitamin K1 warfarin ubiquinone plastoquinone
what is Vitamin E + reacts with what
- an antioxidant
- the aromatic rings reacts with and destroys the most reactive form of oxygen radicals and other free radicals, protecting unsaturated fatty acids from oxidation and preventing oxidative damage to membrane lipids
what is Vitamin K1
a blood-clotting cofactor (cofactor to prothrombin)
what is warfarin
- a blood anticoagulant- it is a synthetic compund that inhibits prothrombin)
role of ubiquinone and plastoquinone
ubiquinone: a mitochondrial electron carrier (coenzyme Q)
plastoquinone: a chloroplast electron carrier
