Fig. 9. Western blot of gel overlay assay. Axonemes from wild-type (wt) and mutant axonemes were subjected to SDS-PAGE and transferred to nitrocellulose membrane. The blot was then incubated with bacterially expressed PF6-IP3. The bound PF6-IP3 was detected using S-protein overlay (see Materials and Methods). PF6-IP3 binds to a polypeptide of molecular weight consistent with that of PF6-IP2 (asterisk). This polypeptide is absent in axonemes isolated from pf6, pf16 and pf18, also consistent with PF6-IP2.