CFAP36 uses "coincidence detection" to bind two IFT subunits only accessible in retrograde trains – ensuring one-way traffic out of cilia! We validated these interactions in vivo by introducing disruptive mutations in the predicted binding interfaces of CFAP36 and IFT - which stalled CFAP36. 6/n

How does CFAP36 bind to retrograde IFT trains though? In an unbiased #AlphaFold2-multimer screen using pairwise predictions of ciliary proteins with CFAP36, we identified subunits of both the IFT-A and -B subcomplexes as potential binding partners. 5/n

Live cell #TIRF imaging of flagella revealed that CFAP36 prefers to travel with retrograde IFT trains moving back to the ciliary base. 4/n

When CFAP36 is depleted in cells, we observed K63-linked ubiquitin accumulating in cilia and disruption of #Hedgehog signaling – a pathway vital for development. This highlights why precise protein export matters for proper signaling. 3/n

We identified #CFAP36 as a missing link in ciliary protein homeostasis: it connects ubiquitinated proteins to the intraflagellar transport #IFT machinery for removal. But CFAP36 doesn’t act alone: it forms a complex with ARL3, a small GTPase previously known for its role during ciliary import. 2/n