RVxP motif

RVxP motif is a protein motif involved in localizing proteins into cilia.
Cilia are sensory organelle of cells, whose malfunction can cause diseases such as polycystic kidney disease, nephronophthisis and Bardet-Biedl syndrome. Proteins employed in the cilia are targeted there when they bear specific entry signals, whereas proteins not situated in cilia are removed or prevented from entering the organelles. Entry signals have been found in ciliary/flagellar proteins of the protozoans "Leishmania" and "Trypanosoma".
The RVxP motif was first described for the PKD2 protein and when inserted in the transferrin receptor it can target it to cilia. It probably carries out its signal function through protein interactions although the exact process and where in the cell it takes place are unknown. Three candidate proteins involved in "receiving" this signal are pericentrin at the basal body of cilia, intraflagellar transport proteins such as IFT57 and ARF4 while the BBSome does not appear to interact with the sequence. The kinesins KIF17 is implicated in transporting the CNGB1 protein which has a RVxP motif into human cilia, as is Rab8a in transporting PKD2. Not all ciliary proteins use a RVxP motif for transport, however; VxPx and Ax(S/A)xQ have also been described as cilium-targeting motifs.
Examples of proteins with RVxP motifs associated with cilia:
Other proteins associated with cilia for which the occurrence of a RVxP motif has been discussed are PKD1 and PSEN2.