ROP effector binding specifically activated ROPs and linking them to the microtubule cytoskeleton. Involved in ROP-regulated polar growth. Involved in local disassembly of cortical microtubules when associated with ARAC10 and KIN13A and conversely mediates also the elimination of ARAC10 from the plasma membrane by the cortical microtubules. Accumulates at the plus end of shrinking microtubules. Targets KIN13A to microtubules. Component of the active ARAC10-IRC5-KIN13A complex (PubMed:24280391). Homooligomer. Interacts (via C-terminus) with ARAC4, ARAC10, ARAC11 and (via N-terminus) with KIN13A (via C-terminus), but no interactions with SEC3A. In xylem cells, preferentially colocalizes with cortical microtubules located beneath the secondary wall pits (PubMed:20619818). May be associated to the plasma membrane through the interaction with ARAC10 (PubMed:22984069). Expressed in xylem cells in the roots and in stamens, petals and pollen. The N-terminal part (1-122) is necessary and sufficient for homooligomerization (PubMed:20832900) and for binding to microtubules while the C-terminal domain is anchored to the plasma membrane (PubMed:20619818). Belongs to the ICR family.