Related Experiment Video
Updated: Aug 24, 2026

Assaying Protein Kinase Activity with Radiolabeled ATP
Published on: May 26, 2017
Solution structure of atypical protein kinase C PB1 domain and its mode of interaction with ZIP/p62 and MEK5
Yoshinori Hirano1, Sosuke Yoshinaga, Kenji Ogura
1Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Hokkaido University, N-12 W-6, Kita-ku, Sapporo 060-0812, Japan.
Abstract:
Atypical protein kinase C (aPKC) has been implicated in several signaling pathways such as cell polarity, cell survival, and cell differentiation. In contrast to other PKCs, aPKC is unique in having the PB1 (Phox and Bem 1) domain in the N terminus. The aPKC PB1 domain binds with ZIP/p62, Par6, or MEK5 through a PB1-PB1 domain interaction that controls the localization of aPKC. Here, we determined the three-dimensional structure of the PB1 domain of PKCiota by NMR and found that the PB1 domain adopts a ubiquitin fold. The OPCA (OPR, PC, and AID) motif inserted into the ubiquitin fold was presented as a betabetaalpha fold in which the side chains of conserved Asp residues were oriented to the same direction to form an acidic surface. This structural feature suggested that the acidic surface of the PKCiota PB1 domain interacted with the basic surface of the target PB1 domains, and this was confirmed in the case of the PKCiota-ZIP/p62 complex by mutational analysis. Interestingly, in the PKCiota PB1 domain a conserved lysine residue was located on the side opposite to the OPCA motif-presenting surface, suggesting dual roles for the PKCiota PB1 domain in that it could interact with either the conserved lysine residue or the acidic residues on the OPCA motif of the target PB1 domains.
Related Concept Videos
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...
MAPK Signaling Cascades
The JAK-STAT Signaling Pathway
Cytoskeletal Linker Proteins - Plakins
Mechanism of Filopodia Formation
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
