Isoform-specific differences between the type Ialpha and IIalpha cyclic AMP-dependent protein kinase anchoring domains revealed by solution NMR.
Cyclic AMP dependent protein kinase (PKA) is controlled, in part, by the subcellular localization of the enzyme (). Discovery of dual specificity anchoring proteins (d-AKAPs) indicates that not only is the type II, but also the type I, enzyme localized (). It appears that the type I enzyme is localized in a novel, dynamic fashion as opposed to the apparent static localization of the type II enzyme. Recently, the structure of the dimerization/docking (D/D) domain from the type II enzyme was solved (). This work revealed an X-type four-helix bundle motif with a hydrophobic patch that modulates AKAP interactions. To understand the dynamic versus static localization of PKA, multidimensional NMR techniques were used to investigate the structural features of the type I D/D domain. Our results indicate a conserved helix-turn-helix motif in the type I and type II D/D domains. However, important differences between the two domains are evident in the extreme NH(2) terminus: this region is extended in the type II domain, whereas it is helical in the type I protein. The NH(2)-terminal residues in RIIalpha contain determinants for anchoring, and the orientation and packing of this helical element in the RIalpha structure may have profound consequences in the recognition surface presented to the AKAPs.
Banky
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P
Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, School of Medicine University of California, San Diego, La Jolla, California 92093-0654, USA.
Newlon
M G
MG
Roy
M
M
Garrod
S
S
Taylor
S S
SS
Jennings
P A
PA
D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002942:Circular Dichroism; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D004926:Escherichia coli / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011485:Protein Binding; D020033:Protein Isoforms; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D020033:Protein Isoforms; D011994:Recombinant Proteins; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases