39-kDa protein modulates binding of ligands to low density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor.
A 39-kDa protein of unknown function has previously been reported to copurify with the low density lipoprotein receptor-related protein (LRP)/alpha 2-macroglobulin receptor. In this study we demonstrate that a recombinant 39-kDa fusion protein can reversibly bind to the 515-kDa subunit of the LRP/alpha 2-macroglobulin receptor. This interaction inhibits the binding and uptake of the receptor's two known ligands: 1) beta-migrating very low density lipoproteins activated by enrichment with apoprotein E and 2) alpha 2-macroglobulin activated by incubation with plasma proteases or methylamine. A potential in vivo role of the 39-kDa protein is to modulate the uptake of apoE-enriched lipoproteins and activated alpha 2-macroglobulin in hepatic and extrahepatic tissues.
Herz
J
J
Department of Molecular Genetics, University of Texas, Southwestern Medical Center, Dallas 75235.
Goldstein
J L
JL
Strickland
D K
DK
Ho
Y K
YK
Brown
M S
MS
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002462:Cell Membrane / Q000737:chemistry; D002788:Cholesterol Esters / Q000378:metabolism; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D007668:Kidney / Q000737:chemistry; D008024:Ligands; D008079:Lipoproteins, VLDL / Q000378:metabolism*; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011971:Receptors, Immunologic / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism; D000511:alpha-Macroglobulins / Q000378:metabolism*
D002788:Cholesterol Esters; D008024:Ligands; D008079:Lipoproteins, VLDL; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D009841:Oligonucleotides; D011506:Proteins; D011971:Receptors, Immunologic; D011994:Recombinant Proteins; D014280:Triglycerides; D000511:alpha-Macroglobulins; D004247:DNA