Possible role of the Golgi apparatus in the assembly of very low density lipoprotein

Journal Article · Sun Apr 01 04:00:00 EDT 1990 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.87.7.2390· OSTI ID:6897182

Bamberger, M J; Lane, M D ^[1]

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1. Johns Hopkins Univ. School of Medicine, Baltimore, MD (USA)

Transit of newly synthesized triacyl(3H)-glycerol through organelles of the secretory system leading to assembly into nascent very low density lipoproteins (VLDLs) or to cytoplasmic storage was investigated in chick hepatocytes. Cells in monolayer culture were pulse-labeled with (2-3H)glycerol, and after different periods of chase with unlabeled glycerol, the movement of triacyl(3H)glycerol through the endoplasmic reticulum (ER) and Golgi and the incorporation into nascent VLDL and cytoplasmic triacylglycerol-rich vesicles (TGRVs) were determined. Initially, newly synthesized triacyl(3H)glycerol is tightly associated with the ER. Movement from the ER of triacyl(3H)glycerol destined for cytoplasmic storage (as TGRVs) is extremely rapid and virtually complete within 8 min of chase. After 8 min of chase, triacyl(3H)glycerol lost from organelles of the secretory system was accounted for entirely as triacyl(3H)glycerol secreted as VLDL. Comparison of the rates of movement of triacyl(3H)glycerol, apolipoprotein B, apolipoprotein II, and apolipoprotein A-I through the ER and Golgi and of their secretion in nascent VLDL suggests that assembly of triacyglycerol with apolipoproteins occurs in the Golgi. Experiments with permeabilized hepatocytes supplemented with cytosol show that newly synthesized triacyl(3H)glycerol and (3H)phospholipid moves from the ER through the full-density range of Golgi elements and is dependent upon supplementary ATP.

• OSTI ID: 6897182
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 87:7; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
ANIMAL CELLS
ANIMALS
ATP
BIOLOGICAL FUNCTIONS
BIOSYNTHESIS
BIRDS
CELL CONSTITUENTS
CELL CULTURES
CELL MEMBRANES
CHICKENS
ENDOPLASMIC RETICULUM
ESTERS
FOWL
FUNCTIONS
GLYCEROL
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LIPIDS
LIPOPROTEINS
LIVER CELLS
MEMBRANE TRANSPORT
MEMBRANES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANOIDS
PERMEABILITY
PROTEINS
SOMATIC CELLS
SYNTHESIS
TRACER TECHNIQUES
TRIGLYCERIDES
TRITIUM COMPOUNDS
VERTEBRATES