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Subcellular localization

cilia

Functional category

• RTK/FGF signaling
• Ciliary assembly/disassembly
• Cilia–cytoskeleton/adhesion links

Function

Proteomics data show that MDH1B, C10ORF53, and AKAP14 were greatly reduced in the AK7-/- cilia (Supplementary Fig. 2, red dots, and Table 1). Though it is not known whether the MDH1/MDH1B heterodimerization affects the catalytic activity (i.e., generating NADH), it appears important for the structural integrity of RS3, because the N-terminal global domain in MDH1B serves as spacer between the neck and the stalk region by interacting with CFAP91, C10ORF53, and AK9 (Fig. 4d, Supplementary Fig. 6d and Supplementary Fig. 7a-b), yet a MDH1B homodimer would sterically clash with the RS3 head structure. The distal part of the stalk is formed by C10ORF53 (10 kDa) that interacts with the N-terminal domain of MDH1B, and the docking domains of both cAMP-dependent protein kinase type II-alpha regulatory subunit (PRKAR2A, 45 kDa) and ciliogenesis-associated TTC17-interacting protein (CATIP, 59 kDa) with a long alpha-helix that is buttressed into the hook-shaped C-terminal end of CFAP91 (Figs. 2a-e, 4d and Supplementary Fig. 7b-c and Supplementary Video 1)(40475651).