Synthesis of Membrane Lipids and Sphingolipidoses

These flashcards cover key concepts and terminology related to the synthesis of membrane lipids and sphingolipidoses, as presented in the lecture.

What are glycerophospholipids?

Abundant membrane phospholipids

Glycerophospholipid components?

Glycerol, 2 FA, phosphate

FA at sn-1 position?

Saturated

FA at sn-2 position?

Unsaturated

Phospholipid synthesis site?

Cytosolic face of ER

Glycerophospholipid precursor?

Phosphatidic acid

Phosphatidic acid starts from?

Glycerol 3-phosphate

Most abundant body phospholipid?

Phosphatidylcholine

Phosphatidylcholine made from?

Phosphatidylethanolamine methylation

What is lung surfactant?

Mixture reducing surface tension

Surfactant prevents what?

Alveoli collapse

Surfactant secreted by?

Type II pneumocytes

Main lung surfactant phospholipid?

Dipalmitoylphosphatidylcholine (DPPC)

DPPC characteristic?

Two palmitoyl fatty acids

Surfactant spreading proteins?

SP-B, SP-C

Surfactant immune defense proteins?

SP-A, SP-D

Surfactant deficiency causes?

Neonatal respiratory distress syndrome

Fetal lung maturity measured by?

Lecithin/sphingomyelin ratio

Mature L/S ratio?

$$>2$$

What insulates nerve axons?

Myelin sheath

Myelinating cells?

Oligodendrocytes (CNS), Schwann (PNS)

CNS demyelination disease?

Multiple sclerosis

Phospholipase cleaves FA at C1?

PLA1

Phospholipase cleaves FA at C2?

PLA2

Phospholipase cleaves phosphate group?

PLC

Phospholipase cleaves head group?

PLD

Enzyme producing arachidonic acid?

PLA2

Arachidonic acid precursor to?

Eicosanoids

PLC second messengers?

DAG, IP3

PLD product?

Phosphatidic acid

Sphingolipid precursor?

Ceramide

Sphingosine formed from?

Serine + palmitoyl-CoA

Sphingosine synthesis enzyme?

Serine palmitoyltransferase

Ceramide + phosphatidylcholine forms?

Sphingomyelin

Ceramide + UDP-glucose forms?

Glucocerebroside

Ceramide + sugars forms?

Glycosphingolipids

Sphingolipid synthesis location?

ER & Golgi

Simplest glycosphingolipids?

Cerebrosides

Cerebroside with glucose?

Glucocerebroside

Cerebroside with galactose?

Galactocerebroside

Sulfated cerebrosides?

Sulfatides

Glycosphingolipids with neutral sugars?

Globosides

Glycosphingolipids with sialic acid?

Gangliosides

Cholera toxin binding site?

GM1 gangliosides

Sphingolipid cell function?

Adhesion, antigens, toxin receptors

What causes sphingolipidoses?

Enzyme deficiency

Result of lysosomal enzyme deficiencies?

Toxic substance accumulation

Most sphingolipidoses inheritance?

Autosomal recessive

X-linked sphingolipidosis?

Fabry disease

Tay-Sachs deficient enzyme?

Hexosaminidase A

Tay-Sachs accumulated lipid?

GM2 ganglioside

Tay-Sachs key symptoms?

Cherry-red macula, psychomotor regression

Niemann-Pick deficient enzyme?

Sphingomyelinase

Niemann-Pick accumulated lipid?

Sphingomyelin

Niemann-Pick key findings?

Hepatosplenomegaly, foam cells

Niemann-Pick neurodegeneration type?

Type A

Niemann-Pick type without CNS?

Type B

Gaucher deficient enzyme?

Glucocerebrosidase

Gaucher accumulated lipid?

Glucocerebroside

Gaucher characteristic cell?

Gaucher cells

Gaucher key symptoms?

Hepatosplenomegaly, bone pain/fractures

Krabbe deficient enzyme?

β-galactosidase

Krabbe accumulated lipid?

Galactocerebroside

Krabbe pathological cells?

Globoid cells

Krabbe neurological finding?

Demyelination

Krabbe early symptoms?

Irritability, feeding difficulty

Fabry deficient enzyme?

α-galactosidase A

Fabry accumulated lipid?

Ceramide trihexoside

Fabry inheritance?

X-linked

Fabry key symptoms?

Angiokeratomas, neuropathy, renal failure

MLD deficient enzyme?

Arylsulfatase A

MLD accumulated lipid?

Sulfatide

MLD hallmark brain finding?

Demyelination

MLD neurological symptoms?

Progressive paralysis, peripheral neuropathy

MLD histological staining?

Metachromasia

GM1 Gangliosidosis deficient enzyme?

β-galactosidase

GM1 Gangliosidosis accumulated lipid?

GM1 ganglioside

GM1 Gangliosidosis key signs?

Cherry-red macula, hepatosplenomegaly

Hurler syndrome deficient enzyme?

α-L-iduronidase

Hurler syndrome accumulated GAGs?

Heparan, dermatan sulfate

Hurler syndrome key symptoms?

Corneal clouding, coarse facies

Hunter syndrome deficient enzyme?

Iduronate sulfatase

Hunter syndrome accumulated GAGs?

Heparan, dermatan sulfate

Hunter syndrome inheritance?

X-linked

Hunter unique physical findings?

Pebbled skin, dysostosis multiplex

Pompe disease deficient enzyme?

Acid α-glucosidase

Pompe disease accumulated substance?

Lysosomal glycogen

Pompe major affected organ?

Heart (cardiomyopathy)

I-cell disease defect?

Mannose-6-phosphate tagging

I-cell consequence?

Lysosomal enzyme trafficking failure

I-cell accumulated substances?

GAGs, sphingolipids

I-cell key physical findings?

Dysostosis multiplex, coarse facies

Phosphatidylserine role?

Cell signaling, apoptosis

Phosphatidylinositol role?

Second messenger precursor

Myelin sphingolipids?

Sphingomyelin, cerebrosides

Amphipathic membrane lipid?

Phospholipids

Ceramide synthesis enzyme?

Ceramide synthase

Ceramide accumulation indicates?

Stress, apoptosis