Densin-180 interacts with delta-catenin/neural plakophilin-related armadillo repeat protein at synapses.
Densin-180, a protein purified from the postsynaptic density fraction of the rat forebrain, is the founding member of a newly described family of proteins termed the LAP (leucine-rich repeats and PSD-95/Dlg-A/ZO-1 (PDZ) domains) family that plays essential roles in establishment of cell polarity. To identify Densin-180-binding proteins, we screened a yeast two-hybrid library using the carboxyl-terminal fragment of Densin-180 containing PDZ domain as bait, and we isolated delta-catenin/neural plakophilin-related armadillo repeat protein (NPRAP) as a Densin-180-interacting protein. delta-catenin/NPRAP, a member of the armadillo repeat family, is a nervous system-specific adherens junction protein originally discovered as an interactor with presenilin-1, a protein involved in Alzheimer's disease. Densin-180 PDZ domain binds the COOH terminus of delta-catenin/NPRAP containing the PDZ domain-binding sequence. Endogenous Densin-180 was co-immunoprecipitated with delta-catenin/NPRAP and N-cadherin. Although Densin-180 was reported to be a transmembrane protein, Densin-180 was not accessible to surface biotinylation in dissociated hippocampal neurons; hence Densin-180 may be a cytosolic protein. Densin-180 co-localized with delta-catenin/NPRAP at synapses in delta-catenin/NPRAP and may be involved in organization of the synaptic cell-cell junction through interaction with the delta-catenin/NPRAP-N-cadherin complex.
Izawa
Ichiro
I
Division of Biochemistry, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, Aichi 464-8681, Japan.
Nishizawa
Miwako
M
Ohtakara
Kazuhiro
K
Inagaki
Masaki
M
D000818:Animals; D051186:Armadillo Domain Proteins; D019921:Biotinylation; D001921:Brain / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D051177:Catenins; D015815:Cell Adhesion Molecules; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D015723:Gene Library; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D010750:Phosphoproteins; D011233:Precipitin Tests; D011485:Protein Binding; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012795:Sialoglycoproteins / Q000737:chemistry* / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism; D014162:Transfection; D020798:Two-Hybrid System Techniques; D000095002:Delta Catenin
D051186:Armadillo Domain Proteins; D015820:Cadherins; D051177:Catenins; D015815:Cell Adhesion Molecules; C484654:Ctnnd2 protein, rat; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; C504461:LRRC7 protein, human; C504463:Lrrc7 protein, rat; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D012795:Sialoglycoproteins; D000095002:Delta Catenin