Research / Clinical Summary

Susan Taylor, PhD Professor, Chemistry & Biochemistry Cancer Biology Program Contact by Email

The primary focus of this laboratory is to understand the structure, function and dynamics of cAMP-dependent protein kinase. This enzyme serves as a prototype for the entire protein kinase family. Functional sites and dynamic properties have been characterized by a variety of chemical, biophysical and recombinant approaches. The role of phosphorylation and myristylation as well as local and global dynamics are being probed.

A crystal structure of the C-subunit solved in 1991, was the first portein kinase structure. This structure provides a structural framework for all protein kinase members. The folding of the polypeptide chain is revealed as well as the location of conserved residues throughout the core. Open and closed conformations provide an indication of the flexibility of the enzyme. Both ATP and peptide binding are clearly delineated. Kinetic studies and fluorescent approaches are being used to define individual steps associated with substrate binding and catalysis. The structure of the RIa and RIIb regulatory subunits have also been solved, and these reveal critical isoform-specific differences. The dimerization domain at the N-terminus serves also as a docking site for A Kinase Anchoring Proteins (AKAPs). The structure of the RIa D/D domain was solved by NMR in collaboration with Dr. Patricia Jennings.

To probe kinase function in eukaryotic cells, we microinject fluorescently labeled proteins as well as plasmids encoding for GFP- or epitope tagged proteins. This approach allows us to look at subcellular localization, translocation to and from the nucleus, and to detect elevated levels of cAMP in individual living cells. We are now characterizing the structure and subcellular localization of two novel AKAPs, DAKAP1 and DAKAP2, that bind to both the RI and RII subunits.


--------------------------------------------------------------------------------

SELECTED PUBLICATIONS

Crystal Structures of the Myristylated Catalytic Subunit of cAMP-dependent Protein Kinase Reveal Open and Closed Confomations. With J. Zheng, D.R. Knighton, N.-h. Xuong, J.M. Sowadski, and L.F. Ten Eyck. Protein Sci. 2, 1559 (1993).

Idenification of a Signal for Rapid Export of Proteins from the Nucleus. With W. Wen, J.L. Meinkoth, and R. Y. Tsien. Cell 82, 1 (1995).

Regulatory (RIa) Subunit of Protein Kinase A: Structure of Deletion Mutant with cAMP Binding Domains. With Y. Su, W.R.G. Dostmann, F.W. Herberg, K. Durick, N.-h. Xuong, L.F. Ten Eyck, and K.I. Varughese. Science 269, 807 (1995).

D-AKAP2, A Novel Protein Kinase A Anchoring Protein with a Putative RGS Domain. With L.J. Huang, K. Durick, J.A. Weiner, and J. Chun. Proc. Natl. Acad. Sci. USA 94, 11184 (1997).

Dimerization/Docking Domain of the Type Ia Regulatory Subunit of PKA: Requirements for Dimerization and Docking Are Distinct but Overlapping. With P. Banky and L.J. Huang. J. Biol. Chem. 273, 35048 (1998).

NH2-Terminal Targeting Motifs Direct Dual Specificity A-Kinase-anchoring Protein 1 (D-AKAP1) to Either Mitochondria or Endoplasmic Reticulum. With L. Huang, L. Wang, Y. Ma, K. Durick, G. Perkins, T.J. Deerinck, and M.H. Ellisman. J. Cell Biol. 145, 951 (1999).

Serine-53 in the Glycine-Rich Nucleotide-Positioning Loop of the cAMP-Dependent Protein Kinase: Role in P-Site Specificity and Interaction with Inhibitors. With R. Aimes and W. Hemmer. Biochem. 39, 8325 (2000).

Update Summary via ONcLINE (password required)
Click here to request a new or forgotten password