Plant cytokinesis requires coordination between the actin cytoskeleton, microtubules, and membranes to guide division plane formation and cell plate expansion
how these regulatory factors are coordinated remains unknown. The actin cytoskeleton assembly is controlled by several actin nucleation factors, such as the SCAR/WAVE complex, which regulates actin nucleation and branching through the activation of the ARP2/3 complex. The activity of these actin regulatory proteins is likely influenced by interactions with specific membranes
however, the molecular basis and the biological relevance of SCAR-membrane interactions are also unclear. In this study, we demonstrate that the ER-PM tethering protein VAP27-1 directly interacts with SCAR2 at the ER membrane and that they colocalize to guide cell plate orientation during cell division. In the root meristem, both VAP27-1 and SCAR2 exhibit polarized localization at the cell plates, where the interaction between ER and PM is abundant. VAP27-1 recruits SCAR2 to the cell division plane, where there is a high concentration of actin filaments. In the