Different ataxin-2 antibodies display different immunoreactive profiles.
We have developed a monoclonal antibody (4A7) directed against the C-terminus of the ataxin-2 protein that is involved in the polyglutamine neurodegenerative disorder spinocerebellar ataxia type 2. Comparison with other ataxin-2 antibodies showed that 4A7 specifically recognized ataxin-2. In contrast, a previously reported ataxin-2 antibody (15F6) did not appear to recognize full-length ataxin-2 in our systems. Immunocytochemical and subcellular fractionation studies using 4A7 confirmed previous reports that ataxin-2 is localized to both the cytoplasm and the trans-Golgi network in rat PC12 cells and rat brain tissue. In contrast, 4A7 failed to label the trans-Golgi network in the three primate cell lines examined. Cytoplasmic ataxin-2 was not associated with mitochondria, lysosomes, endoplasmic reticulum, peroxisomes, proteasomes, clathrin-coated pits or vesicles, or F-actin. Ataxin-2 was found to be phosphorylated but not glycosylated, and exhibited an estimated half-life of not less than 21 h. Interestingly, another commercially available ataxin-2 antibody did not detect ataxin-2 localized to the trans-Golgi network. This antibody was also found to immunoprecipitate fewer proteins/protein partners than 4A7. Although cross-reactivity of the 4A7 antibody with other protein(s) cannot be ruled out, it appears likely that the interaction of ataxin-2 with other cell components is dependent on both the host cell type and its subsequent subcellular localization.
Turnbull
Victor J
VJ
Van Cleef/Roet Centre for Nervous Diseases and Department of Neuroscience, Monash University (Alfred Hospital), Melbourne, Australia.
Storey
Elsdon
E
Tarlac
Volga
V
Walsh
Renae
R
Stefani
Daniela
D
Clark
Robert
R
Kelly
Louise
L
D000818:Animals; D000911:Antibodies, Monoclonal / Q000145:classification / Q000276:immunology* / Q000378:metabolism; D015703:Antigens, CD / Q000378:metabolism; D000067528:Ataxins; D015153:Blotting, Western / Q000379:methods; D045744:Cell Line, Tumor; D002966:Clathrin / Q000378:metabolism; D005455:Fluorescent Antibody Technique / Q000379:methods; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins; D009447:Neuroblastoma / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011506:Proteins / Q000276:immunology*; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000067528:Ataxins; D002966:Clathrin; D006023:Glycoproteins; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins; C072237:TGOLN2 protein, human; C513045:Tgoln2 protein, rat; D046988:Proteasome Endopeptidase Complex