Related Experiment Video
Updated: Mar 29, 2026

Assaying Protein Kinase Activity with Radiolabeled ATP
Published on: May 26, 2017
Defining A-Kinase Anchoring Protein (AKAP) Specificity for the Protein Kinase A Subunit RI (PKA-RI)
Karolin Autenrieth1, N George Bendzunas2, Daniela Bertinetti1
1Dept. of Biochemistry, Universitat Kassel, Heinrich Plett Strasse 40, Kassel 34132 (Germany).
Abstract:
A-Kinase anchoring proteins (AKAPs) act as spatial and temporal regulators of protein kinase A (PKA) by localizing PKA along with multiple proteins into discrete signaling complexes. AKAPs interact with the PKA holoenzyme through an α-helix that docks into a groove formed on the dimerization/docking domain of PKA-R in an isoform-dependent fashion. In an effort to understand isoform selectivity at the molecular level, a library of protein-protein interaction (PPI) disruptors was designed to systematically probe the significance of an aromatic residue on the AKAP docking sequence for RI selectivity. The stapled peptide library was designed based on a high affinity, RI-selective disruptor of AKAP binding, RI-STAD-2. Phe, Trp and Leu were all found to maintain RI selectivity, whereas multiple intermediate-sized hydrophobic substitutions at this position either resulted in loss of isoform selectivity (Ile) or a reversal of selectivity (Val). As a limited number of RI-selective sequences are currently known, this study aids in our understanding of isoform selectivity and establishing parameters for discovering additional RI-selective AKAPs.
Related Concept Videos
PI3K/mTOR/AKT Signaling Pathway
Small GTPases - Ras and Rho
Three regulatory proteins control their activity:
Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein Kinases and Phosphatases
Lipids as Anchors
The carboxy-terminal of most of the prenylated proteins, such as Ras proteins, contains...

