Mouse Na+/K+-ATPase beta1-subunit has a K+-dependent cell adhesion activity for beta-GlcNAc-terminating glycans.
A 48-kDa beta-N-acetylglucosamine (GlcNAc)-binding protein was isolated from mouse brain by GlcNAc-agarose column chromatography. The N-terminal amino acid residues showed the protein to be a mouse Na(+)/K(+)-ATPase beta1-subunit. When the recombinant FLAG-beta1-subunit expressed in Sf-9 cells was applied to a GlcNAc-agarose column, only the glycosylated 38- and 40-kDa proteins bound to the column. In the absence of KCl, little of the proteins bound to a GlcNAc-agarose column, but the 38- and 40-kDa proteins bound in the presence of KCl at concentrations above 1 mM. Immunohistochemical study showed that the beta1-subunit and GlcNAc-terminating oligosaccharides are at the cell contact sites. Inclusion of anti-beta1-subunit antibody or chitobiose in cell aggregation assays using mouse neural cells resulted in inhibition of cell aggregation. These results indicate that the Na(+)/K(+)-ATPase beta1-subunit is a potassium-dependent lectin that binds to GlcNAc-terminating oligosaccharides: it may be involved in neural cell interactions.
Kitamura
Noriaki
N
Department of Biosignal Research, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan.
Ikekita
Masahiko
M
Sato
Takeshi
T
Akimoto
Yoshihiro
Y
Hatanaka
Yasumaru
Y
Kawakami
Hayato
H
Inomata
Mitsushi
M
Furukawa
Kiyoshi
K
D000117:Acetylglucosamine / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism; D002448:Cell Adhesion; D004187:Disaccharides / Q000494:pharmacology; D006031:Glycosylation; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011134:Polysaccharides / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology*; D021122:Protein Subunits; D012685:Sepharose / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis / Q000737:chemistry / Q000502:physiology*
D004187:Disaccharides; D011134:Polysaccharides; D021122:Protein Subunits; C032438:chitobiose; D012685:Sepharose; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium; D000117:Acetylglucosamine