Interaction of the regulatory subunit (RII) of cAMP-dependent protein kinase with RII-anchoring proteins occurs through an amphipathic helix binding motif
The type II cAMP-dependent protein kinase is localized to specific subcellular environments through the binding of the regulatory subunit (RII) dimer to RII-anchoring proteins. Computer-aided analysis of secondary structure, performed on four RII-anchoring protein sequences (the microtubule-associat...
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Published in | The Journal of biological chemistry Vol. 266; no. 22; pp. 14188 - 14192 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Society for Biochemistry and Molecular Biology
05.08.1991
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Subjects | |
Online Access | Get full text |
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Summary: | The type II cAMP-dependent protein kinase is localized to specific subcellular environments through the binding of the regulatory
subunit (RII) dimer to RII-anchoring proteins. Computer-aided analysis of secondary structure, performed on four RII-anchoring
protein sequences (the microtubule-associated protein 2, P150, and two thyroid proteins Ht 21 and Ht 31), has identified common
regions of approximately 14 residues which display high probabilities of forming amphipathic helices. The potential amphipathic
helix region of Ht 31 (Leu-Ile-Glu-Glu-Ala-Ala-Ser-Arg-Ile-Val-Asp-Ala-Val-Ile) lies between residues 494 and 507. A bacterially
expressed 318-amino acid fragment, Ht 31 (418-736), containing the amphipathic helix region, was able to bind RII alpha. Site-directed
mutagenesis designed to disrupt the secondary structure in the putative binding helix reduced binding dramatically. Specifically,
substitution of proline for Ala-498 significantly diminished RII alpha binding, and similar mutation of Ile-502 or Ile-507
abolished interaction. Mutation of Ala-522 to proline, which is located outside the predicted amphipathic helix region, had
no effect on RII alpha binding. These data suggest that anchoring proteins interact with RII alpha via an amphipathic helix
binding motif. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/S0021-9258(18)98665-5 |