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103 Cards in this Set
- Front
- Back
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where are chylomicrons made?
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intestines
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what are chylomicrons?
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exogenous lipoprotein particles
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what are the endogenous lipoprotein particles?
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VLDL
IDL LDL HDL |
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where are HDLs made?
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in intestines
mostly in liver |
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what is the lipoprotein particle involved in reverse cholesterol transport?
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HDL
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what is reverse cholesterol transport?
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transportation of cholesterol from non-hepatic tissues back to liver
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what are scavenger cells?
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monocytes
macrophages |
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what is the substrate for lipoprotein lipase?
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HDLs
LDLs VLDLs IDLs |
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what is the central organ in cholesterol transport?
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liver
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what is an apolipoprotein?
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the proteinaceous part of a lipoprotein
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with what type of lipoprotein particles does apoA-I associate?
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chylomicron
HDL |
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what is the major protein of HDLs?
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apoA-I
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what apolipoprotein activates LCAT?
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apoA-I
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what apolipoprotein enhances hepatic lipase?
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apoA-II
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with what type of lipoprotein particles does apoA-II associate?
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chylomicron
HDL |
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with what type of lipoprotein particle does apoB-48 associate?
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Chylomicron
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how is apoB-48 produced?
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RNA editing of B-100 RNA
(from same gene) |
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what apolipoprotein is exclusive to chylomicrons?
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apoB-48
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with what type of lipoprotein particle does apoB-100 associate?
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VLDL
IDL LDL |
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what is the major protein of LDL?
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apoB-100
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what apolipoprotein binds to the LDL receptor?
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apoB-100
apoE |
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what is the largest known human protein?
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apoB-100
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with what type of lipoprotein particle does ApoC-II associate?
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chylomicron remnants
VLDL LDL HDL |
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what apolipoprotein activates lipoprotein lipase?
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apoC-II
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what apolipoprotein inhibits lipoprotein lipase?
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apoC-III
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with what lipoprotein particles does apoC-III associate?
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chylomicron remnants
VLDL LDL HDL |
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which apolipoprotein is exclusive to HDL?
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apoD
Cholesterol Ester Transport Protein (CETP) |
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with what type of lipoprotein particle does apoD associate?
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HDL
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with what type of lipoprotein particle does apoE associate?
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chylomicron remnants
VLDL LDL HDL |
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which apolipoprotein has numerous isoforms, including one associated with late onset Alzheimer's?
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apoE
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which isoform of apoE is associated with late onset Alzheimer's?
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apoEepsilon-4
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with what type of lipoprotein particle does apo(a) associate?
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LDL
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what does Lp(a) resemble?
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plasminogen
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what is Lp(a)?
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LDL bound to apo(a) disulfide bonded to apoB-100
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what are the dietary lipoprotein particles?
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chylomicrons
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what is the predominant carrier of triacylglycerols from diet?
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chylomicrons
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what apolipoproteins are present in chylomicrons?
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apoB-48
apoA-I apoA-II apoA-IV |
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where do chylomicrons enter blood?
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left subclavian vein
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what apolipoproteins are acquired by chylomicrons from HDLs?
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apoC-II
apoE |
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what apolipoprotein is required by chylomicrons to activate lipoprotein lipase?
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apoC-II
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what apolipoproteins are transferred from chylomicrons to HDLs?
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apoAs
apoCs |
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what is required for chylomicron remnants to enter the liver?
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LDL receptor-related protein (LRP)
apoE |
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where are VLDLs made?
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liver
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how do VLDLs transport cholesterol?
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cholesteryl esters
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what apolipoproteins are present in VLDLs?
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apoB-100
apoC-I apoC-II apoC-III apoE |
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what apolipoproteins are acquired by VLDLs from HDLs?
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apoCs
apoE |
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what apolipoproteins are transferred from VLDLs to HDLs?
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apoCs
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what apolipoproteins are required for IDL and LDL uptake by hepatocytes?
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apoB-100
apoE |
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what happens when apoE is lost from the system?
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severe atherosclerosis
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when taken up by cells, what enzyme esterifies excess cholesterol?
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ACAT
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what is ACAT?
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acyl-CoA:cholesterol acyl transferase
intracellular protein that puts acyl group on cholesterol |
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what is LCAT?
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lecithin-cholesterol acyltransferase
enzyme that converts free cholesterol into cholesteryl esters |
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what apolipoproteins are present in HDLs?
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apoA-I
apoC-I apoC-II apoE |
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what is the major function of HDLs?
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to be a circulating store of apoC-I, apoC-II, and apoE
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where is LCAT found?
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in HDLs
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what does LCAT do?
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esterifies cholesterol in chylomicrons and IDLs
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what apolipoprotein is required by LCAT?
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apoA-I
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what is the only form of cholesterol that can be returned to liver?
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cholesterol esters
by HDLs |
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what is SR-B1?
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scavenger receptor type B1
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what is the receptor for HDLs? what cells in have this receptor?
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SR-B1
hepatic macrophages |
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what apolipoprotein allows HDLs to transfer cholesterol from HDLs to VLDLs and LDLs?
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apoD (CETP)
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what is the most common lipoprotein receptor?
what is its function? |
LDL receptor
LDL uptake by liver |
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what is another name for the LDL receptor?
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apoB-100/apoE receptor
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what does the extracellular domain of LDL receptor bind?
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apoE and apoB-100
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what does the intracellular domain of LDL receptor do?
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clusters LDL receptors in coated pits
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what lipoprotein receptors are co-receptors in Wnt signalling?
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LDL receptor-related proteins (LRP) 5/6
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what happens to SR-B1 when it complexes to HDL?
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it stays on the cell surface
(cholesterol is passed to another protein) |
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what is lipoprotein-associated PLA2 primarily associated with? through what apolipoprotein does it act?
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LDLs
apoB-100 |
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what do increased levels of plasma Lp-PLA2 double?
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risk for primary and secondary cardiovascular events
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to what are the antiatherogenic functions of Lp-PLA2 attributed?
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its role in hydrolyzing and inactivating PAF and oxPLs
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to what are the proatherogenic and proinflammatory actions of Lp-PLA2 attributed?
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hydrolysis of oxPLs releasing both lyso-PC and oxFFA (both have proatherogenic effects)
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what is the most common genetic defect in cholesterol biosynthesis?
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defect in 7-dehydrocholesterol reductase
Smith-Lemli-Optiz syndrome (SLOS) |
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what are the effects of Smith-Lemli-Optiz Syndrome?
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low cholesterol
high 7-dehydrocholesterol |
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what are the symptoms of SLOS?
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mental retardation
microcephaly genital anomalies postnatal growth retardation syndactyly of second and third toes |
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what causes the developmental anomalies in SLOS?
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role of cholesterol in modification of shh
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what is shh?
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sonic hedgehog gene
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what is the cause of Tangier disease?
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defects in ABCA1
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what is the purpose of ABCA1?
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transporter in cholesterol export from cells
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what effect does ABCA1 have on inflammation?
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suppresses macrophage inflammation by facilitating efflux of cholesterol to HDLs
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what are the symptoms of Tangier disease? the hallmark symptom?
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hepatosplenomegaly
peripheral neuropathy weakness of limb and facial muscles sensory losses in face and limbs hallmark sign is hyperplastic orange tonsils |
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what are the primary lipoproteins that accumulate in the vessel wall during atherosclerosis?
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LDL and ox LDL
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what causes leukocyte adhesion, vascular permeability, and thrombosis in atherosclerosis?
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endothelial injury
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what effect does the accumulation of lipoproteins have on monocytes during atherosclerotic development?
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causes them to adhere, then migrate and differentiate into macrophages, finally becoming foam cells
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what leads to smooth muscle cell recruitment from circulating precursors?
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cytokine and growth factor release from activated platelets, macrophages, and vessel wall cells
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what are the steps in the progression of atherosclerosis?
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endothelial injury -> leukocyte adhesion, vascular permeability, thrombosis -> accumulation of lipoproteins in vessel wall -> monocyte adhesion, migration, and transformation -> platelet adhesion -> smooth muscle cell recruitment -> SMC proliferation and ECM deposition -> lipd accumulation
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where does lipid accumulate during atherosclerosis?
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extracellularly
within macrophages within smooth muscle cells |
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patients with which disorders have Lp-x circulating in their blood?
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patients with LCAT deficiency
patients with cholestatic liver disease |
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what is the terminal protein in hemostasis?
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plasminogen
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what is the purpose of plasminogen?
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cleaved to plasmin which then dissolves the fibrin which forms clots
(enzymatic activity is in the kringle domains) |
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what competes with plasminogen for activators and for sites on fibrin clots?
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apo(a)
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how is apo(a) similar to plasminogen? how is it different?
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has repeating kringle domains
kringle domains aren't enzymatically active |
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how much do the concentrations of apo(a) vary between individuals?
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1000 fold differences
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what is type IIa hyperlipoproteinemia?
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familial hypercholesterolemia
defect in LDL receptor |
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how common is the heterozygous familial hypercholesterolemia?
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1:500
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what are the symptoms of heterozygous familial hypercholesterolemia?
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elevated cholesterol (300-600 mg/dL)
manifests with xanthomas |
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what are xanthomas?
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cholesterol deposits
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what are the symptoms of homozygous familial hypercholesterolemia?
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extremely elevated cholesterol (600-1200 mg/dL)
death in 2nd or 3rd decade from coronary artery disease |
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what is the normal pathway for LDL receptor?
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LDL binding -> internalization -> lysosomal hydrolysis -> regulatory actions
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what are the five processes which have been shown to have defects causing familial hypercholesterolemia?
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synthesis of LDLs
transfer from ER to golgi binding of LDL clustering in coated pits recycling of LDLs |
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what are the limits for HDL on a lipid profile?
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<40 mg/dL is low
>60 mg/dL is high |
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what are the normal levels for total cholesterol?
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<19 years old should have <170mg/dL
>19 years old should have <200mg/dL |
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what are the limits for triglyceride levels on a lipid profile?
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<150mg/dL is normal
150-199 mg/dL is borderline high 200-499 mg/dL is high >500 mg/dL is very high |
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what are the limits for LDL on a lipid profile?
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<100mg/dL is optimal
100-129 mg/dL is near optimal 130-159 mg/dL is borderline high 160-189 mg/dL is high >190 mg/dL is very high |
