Ensures, when in complex with FPP3/VETH1 and COG2, the correct secondary cell wall (SCW) deposition pattern by recruiting exocyst components to cortical microtubules in xylem cells during secondary cell wall deposition by recruiting EXO70A1. Interacts with WPP/MAF proteins (By similarity). Binds to COG2; this interaction promotes the association between cortical microtubules and EXO70A1 (PubMed:25541219). Present in vesicle-like small compartments which exhibit microtubule plus-end-directed and end-tracking dynamics. Accumulates in preferentially xylem cells. Belongs to the FPP family.