Separation and detection of large phosphoproteins using Phos-tag SDS-PAGE.
We provide a standard phosphate-affinity SDS-PAGE (Mn(2+)-Phos-tag SDS-PAGE) protocol, in which Phos-tag is used to analyze large phosphoproteins with molecular masses of more than 200 kDa. A previous protocol required a long electrophoresis time of 12 h for separation of phosphoisotypes of large proteins ( approximately 150 kDa). This protocol, which uses a 3% (wt/vol) polyacrylamide gel strengthened with 0.5% (wt/vol) agarose, permits the separation of protein phosphoisotypes larger than 200 kDa within 2 h. In subsequent immunoblotting, phosphoisotypes of high-molecular-mass proteins, such as mammalian target of rapamycin (289 kDa), ataxia telangiectasia-mutated kinase (350 kDa) and p53-binding protein 1 (213 kDa), can be clearly detected as up-shifted migration bands on the improved Mn(2+)-Phos-tag SDS-PAGE gel. The procedure from the beginning of gel preparation to the end of electrophoresis requires about 4 h in this protocol.
Department of Functional Molecular Science, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Hiroshima, Japan. kinoeiji@hiroshima-u.ac.jp
Eiji
E
Kinoshita
Emiko
E
Kinoshita-Kikuta
Tohru
T
Koike
D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D024202:Electrophoretic Mobility Shift Assay; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry; D008345:Manganese; D010750:Phosphoproteins / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry; D058570:TOR Serine-Threonine Kinases; D025521:Tumor Suppressor Proteins / Q000737:chemistry; D000071857:Tumor Suppressor p53-Binding Protein 1
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; C498301:TP53BP1 protein, human; D025521:Tumor Suppressor Proteins; D000071857:Tumor Suppressor p53-Binding Protein 1; D008345:Manganese; D011494:Protein Kinases; C546842:MTOR protein, human; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D058570:TOR Serine-Threonine Kinases