Association of a 14-3-3 protein with CMP-NeuAc:GM1 alpha 2,3-sialyltransferase.
CMP-NeuAc:GM1 alpha 2,3-sialyltransferase (ST-IV) was purified to homogeneity from rat brain. Microsequencing of the tryptic peptides derived from the purified enzyme revealed two amino acid sequences homologous to the 14-3-3 proteins. A polyclonal antibody was raised against purified ST-IV. A 33 kDa protein was co-immunoprecipitated from rat brain extracts with the anti-(ST-IV) antibody as detected by Western blot analysis. This protein was identified as a subtype of 14-3-3 family by an anti-(14-3-3) antibody. Screening of a rat brain lambda gt11 library using the anti-(ST-IV) antibody resulted in the identification of a cDNA clone coding for the subtype of 14-3-3 protein. These results indicate an association of the 14-3-3 protein with the sialyltransferase. Since the 14-3-3 protein has PKC inhibitor activities and the activity of sialyltransferases is, at least in part, regulated by PKC, the association of the 14-3-3 protein with ST-IV may indicate a role for this protein in the post-translational regulation of the sialyltransferase activity through the processes of phosphorylation and dephosphorylation.
Gao
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Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0614, USA.
Gu
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Yu
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Yu
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Zeng
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D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology*; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012799:Sialyltransferases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D014162:Transfection; D014446:Tyrosine 3-Monooxygenase; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase
D048948:14-3-3 Proteins; D010446:Peptide Fragments; D011506:Proteins; D011994:Recombinant Proteins; D014446:Tyrosine 3-Monooxygenase; D012799:Sialyltransferases; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase