Member of the RopGEF (guanine nucleotide exchange factor) family, containing the novel PRONE domain (plant-specific Rop nucleotide exchanger), which is exclusively active towards members of the Rop subfamily, also known as DUF315). Interacts with ROP1 but the whole protein lacks Rho guanyl-nucleotide exchange factor activity in vitro. The DUF315/PRONE domain is sufficient to confer RopGEF catalytic activity. ropgef1 mutants have defects in auxin transport that result in abnormal development of embryos and growth defects.
Guanine-nucleotide exchange factor (GEF) that acts as an activator of Rop (Rho of plants) GTPases by promoting the exchange of GDP for GTP. Acts downstream of PRK2 in the control of polarized pollen tube growth by activating ARAC11/ROP1. In association with ROPGEF4, acts as a specific regulator of ARAC10/ROP11 function in ABA-mediated stomatal closure. May play a role in the Rac/Rop-signaling pathway that controls ROS-mediated root hair development.
Localizes to the apical region of the pollen tube plasma membrane to activate ARAC11/ROP1 and interacts with ARAC10/ROP11 on plasma membrane in guard cells.