Lipoprotein binding and endosomal itinerary of the low density lipoprotein receptor-related protein in rat liver

Journal Article · Thu Nov 30 23:00:00 EST 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.86.23.9318· OSTI ID:6921652

Lund, H; Takahashi, K; Hamilton, R L; Havel, R J ^[1]

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1. Univ. of California, San Francisco (USA)

The high affinity of {sup 45}Ca binding to the low density lipoprotein receptor (LDL-R) and the LDL-R-related protein (LRP) was utilized to study the subcellar distribution of these two proteins in rat liver. Like the LDL-R, LRP was manyfold enriched in rat liver endosomal membranes with a relative distribution in early and late endosomal compartments consistent with recycling between endosomes and the cell surface. The high concentration of LRP in hepatic endosomal membranes greatly facilitated demonstration of Ca-dependent binding of apolipoprotein E- and B-containing lipoproteins in ligand blots. LRP was severalfold more abundant than the LDL-R in hepatic parenchymal cells, showed extensive degradation in hepatic endosomes, and was found in high concentrations in the Golgi apparatus and endoplasmic reticulum. These data suggest a high a rate of synthesis of LRP that appeared to be unaffected by treatment of rats with estradiol. The repeating cysteine-rich A-motif found in the ligand-binding domain of LRP appeared to be responsible for Ca binding by LRP, LDL-R, and complement factor C9 and accounted for immunological cross-reactivity among these proteins. The data suggest an extensive proteolytic processing of this protein and are consistent with a functional role of LRP in lipoprotein metabolism.

• OSTI ID: 6921652
• 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. 86:23; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH ISOTOPES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CALCIUM 45
CALCIUM ISOTOPES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
CONNECTIVE TISSUE CELLS
CROSS-LINKING
CYSTEINE
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISTRIBUTION
ENDOPLASMIC RETICULUM
ESTRADIOL
ESTRANES
ESTROGENS
EVEN-ODD NUCLEI
FIBROBLASTS
GLANDS
HORMONES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGANDS
LIPIDS
LIPOPROTEINS
LIVER
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOIDS
ORGANS
POLYMERIZATION
PROTEINS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
SOMATIC CELLS
STEROID HORMONES
STEROIDS
SUBCELLULAR DISTRIBUTION
THIOLS
VERTEBRATES