Biochemical and immunochemical evidence that the "major postsynaptic density protein" is a subunit of a calmodulin-dependent protein kinase
Abstract
By three criteria, two biochemical and one immunochemical, the major postsynaptic density protein (mPSDp) is indistinguishable from the 50-kilodalton (kDa) α subunit of a brain calmodulin-dependent protein kinase. First, the two proteins comigrate on NaDodSO4/polyacrylamide gels. Second, iodinated tryptic peptide maps of the two are identical. Finally, a monoclonal antibody (6G9) that was raised against the protein kinase binds on immunoblots to a single 50 kDa band in crude brain homogenates and to both the subunit of the purified kinase and the mPSDp from postsynaptic density fractions. The purified kinase holoenzyme also contains a 60-kDa subunit termed ß.A comparison of the peptide map of ß with the maps of 60-kDa proteins from the postsynaptic density fraction suggests that ß is present there but is not the only protein present in this molecular weight range. These results indicate that the calmodulin-dependent protein kinase is a major constituent of the postsynaptic density fraction and thus may be a component of type I postsynaptic densities.
Additional Information
© 1983 by the National Academy of Sciences. Communicated by Norman Davidson, August 18, 1983. We thank Jeremy Brockes for use of his tissue culture facilities and members of his laboratory -- in particular, Chris Kintner, Larry Fritz, and Greg Lemke -- for help with the monoclonal antibody work. We also thank Valerie Krieger for technical assistance and Caren Oto for help in preparation of the manuscript. This investigation was supported in part by National Institutes of Health Grants NS 17660 and 1 T 32 GM07616 and by a Gordon Ross Fellowship. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.Files
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Additional details
- PMCID
- PMC390054
- Eprint ID
- 8849
- Resolver ID
- CaltechAUTHORS:KENpnas83
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2007-09-21Created from EPrint's datestamp field
- Updated
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2019-10-02Created from EPrint's last_modified field