Association of membrane-bound amyloid precursor protein APP with the apolipoprotein E receptor LRP.
In order to identify cell surface proteins that interact with the amyloid precursor protein (APP), we biotinylated H4 human neuroglioma cells in culture with a water soluble biotinylating agent, immunoprecipitated APP with an antibody specific to the intracellular domain, and probed the precipitated proteins with anti-biotin. In human neuroglioma cells overexpressing APP751, we found a high molecular weight protein that immunoprecipitated with APP. This band was identified as the low density lipoprotein receptor-related protein (LRP) by three criteria: first, the band immunolabeled with anti-LRP antibodies; second, the band bound the LRP receptor associated protein, RAP; and third, this band was present in LRP-expressing fibroblasts, but not LRP-deficient fibroblasts. In complementary experiments, we found that APP co-precipitated with LRP, with a preference for an isoform of APP containing the Kunitz protease inhibitor domain. Interaction of APP and LRP on the surface of living cells was demonstrated by crosslinking APP and LRP with the water-soluble cross-linking agent BS(3). APP and LRP were shown by confocal microscopy to colocalize in perinuclear structures, but to primarily remain separate in vesicles and on the cell surface. We propose that full-length APP can transiently interact with the receptor LRP on the cell surface, affecting the processing and intracellular transport of APP.
Alzheimer Research Unit, 149 13th Street, Massachusetts General Hospital, Charlestown, MA 02129, USA. rebeck@helix.mgh.harvard.edu
G W
GW
Rebeck
R D
RD
Moir
S
S
Mui
D K
DK
Strickland
R E
RE
Tanzi
B T
BT
Hyman
D000544:Alzheimer Disease / Q000378:metabolism; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal; D016466:CHO Cells; D006224:Cricetinae; D003432:Cross-Linking Reagents / Q000378:metabolism; D005910:Glioma; D006801:Humans; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D010455:Peptides; D010940:Plant Proteins; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D018110:Receptors, Lipoprotein / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D014361:Trypsin Inhibitors / Q000737:chemistry; D014407:Tumor Cells, Cultured
D016564:Amyloid beta-Protein Precursor; D000911:Antibodies, Monoclonal; D003432:Cross-Linking Reagents; C053865:Kunitz-type protease inhibitor, plant; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008565:Membrane Proteins; D010455:Peptides; D010940:Plant Proteins; D018110:Receptors, Lipoprotein; D014361:Trypsin Inhibitors