Fig. 1: Imaging approach to visualize individual kinesin-II (KAP-1::eGFP) molecules entering the cilia of PHA/PHB neurons.

a Illustration of single-molecule imaging of kinesin-II motors entering the sensory cilia of PHA/PHB neurons located in the tail of C. elegans, using small-window illumination microscopy (SWIM). Using SWIM, we can visualize not-yet-photobleached kinesin-II molecules in a small excitation window (~10–15 μm) for a long duration of time. b Illustration of the axonemal structure at initial part of the cilia. The axoneme starts at ciliary base, passes through the TZ between ~300–1000 nm, moving into the proximal segment. c Maximum projection of eGFP-labeled kinesin-II (KAP-1::eGFP) imaged in PHA/PHB cilia of a worm (see Supplementary Movie 2a). Tracks of single-molecule events entering cilium 1 have been indicated (green lines), b indicates the base of the two cilia (dotted red lines) and d indicates the region where the corresponding dendrites are located (between the solid red lines). d Representative kymograph (space-time intensity plot) of kinesin-II along cilium 1, in (c), displays that single kinesin-II molecules, diffusing in the dendrite, dock at the ciliary base and enter the cilium. Single-molecule entry events are tracked (tracks indicated in green).