Intracellular binding of fukutin and alpha-dystroglycan: relation to glycosylation of alpha-dystroglycan.
The functions of fukutin, a gene product responsible for Fukuyama type congenital muscular dystrophy, still remain unclear, although a relation to the glycosylation of alpha-dystroglycan is presumed. To investigate the functions of fukutin, immunohistochemistry, examination using cultured astrocytes, enzyme-linked immunosorbent assay (ELISA)-based binding assay and immunoprecipitation were performed using control muscle and central nervous system tissues. Immunohistochemistry showed that alpha-dystroglycan and fukutin were co-expressed, especially in the glial cytoplasm and glia limitans of the central nervous system. An anti-fukutin antibody added to the culture medium did not bring about any changes in the astrocytes cultured on laminin-coated dishes. Together with the immunohistochemical results, the intracellular function of fukutin is considered. ELISA-based binding assay and immunoprecipitation may suggest the direct binding of fukutin and alpha-dystroglycan, at least in part. Fukutin seems to bind to both the hypoglycosylated and fully glycosylated form of alpha-dystroglycan, and seems bind to the core area rather than the sugar chain of alpha-dystroglycan. Fukutin may directly interact with alpha-dystroglycan during glycosylation, but further examinations are needed to confirm these details.
Yamamoto
Tomoko
T
Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan. sheto@research.twmu.ac.jp
Kawaguchi
Motoko
M
Sakayori
Noriko
N
Muramatsu
Fumiaki
F
Morikawa
Shunichi
S
Kato
Yoichiro
Y
Shibata
Noriyuki
N
Kobayashi
Makio
M
D001253:Astrocytes / Q000378:metabolism; D015153:Blotting, Western; D002478:Cells, Cultured; D049030:Dystroglycans / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D008364:Mannosyltransferases / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism
C113587:FKTN protein, human; D005904:Glial Fibrillary Acidic Protein; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D049030:Dystroglycans; D008364:Mannosyltransferases; D017351:N-Acetylglucosaminyltransferases; C443106:protein O-mannose beta-1,2-N-acetylglucosaminyltransferase; C082696:protein O-mannosyltransferase