A flagellar a-kinase anchoring protein with two amphipathic helices forms a structural scaffold in the radial spoke complex

Priyanka Sivadas, Jennifer M. Dienes, Martin St Maurice, William D. Meek, Pinfen Yang

Research output: Contribution to journalArticle

19 Scopus citations


A-kinase anchoring proteins (AKAPs) contain an amphipathic helix (AH) that binds the dimerization and docking (D/D) domain, RIIa, in cAMP-dependent protein kinase A (PKA). Many AKAPs were discovered solely based on the AH-RIIa interaction in vitro. An RIIa ora similar Dpy-30 domain is also present in numerous diverged molecules that are implicated in critical processes as diverse as flagellar beating, membrane trafficking, histone methylation, and stem cell differentiation, yet these molecules remain poorly characterized. Here we demonstrate that an AKAP, RSP3, forms a dimeric structural scaffold in the flagellar radial spoke complex, anchoring through two distinct AHs, the RIIa and Dpy-30 domains, in four non-PKA spoke proteins involved in the assembly and modulation of the complex. Interestingly, one AH can bind both RIIa and Dpy-30 domains in vitro. Thus, AHs and D/D domains constitute a versatile yet potentially promiscuous system for localizing various effector mechanisms. These results greatly expand the current concept about anchoring mechanisms and AKAPs.

Original languageEnglish
Pages (from-to)639-651
Number of pages13
JournalJournal of Cell Biology
Issue number4
StatePublished - 1 Nov 2012


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