The tail domain of the plant kinesin-12 POK2 is a versatile interaction hub

Tissue development and function rely on correct cell patterning. In plants, patterns are determined by the new cell wall formed during mitosis. During preprophase in embryophytes, ring-like positional cues already mark the future division plane on the plasma membrane. These cues include the kinesin-12 motors PHRAGMOPLAST ORIENTING KINESIN 2 (POK2, also known as KIN12D) and its paralogue POK1 (KIN12C). They are essential for correctly aligning the phragmoplast - a microtubule scaffold for cell wall formation. Although we have a basic understanding of how these motors align the phragmoplast, we currently lack information on how they are targeted to and maintained at the plasma membrane. Here, we reconstituted recombinant POK2 tail fragments on microtubules and vesicles in vitro. We found that the POK2 tail interacted with microtubules, the microtubule-associated protein MAP65-3, as well as with certain anionic lipids. We identified a short element in the POK2 tail responsible for all three interactions. Our data suggest a sequential and cooperative mechanism that targets POK2 specifically to the future division site. There, it is robustly maintained through interactions with the plasma membrane to establish the cell division plane.