Mostly expressed in pollen. Also detected in lateral roots and radicles. Up-regulated by brassinolides. Down-regulated by 2-aminoethoxyvinylglycine (AVG), high CO(2), isoxaben, and propiconazole treatments. Belongs to the TRAFAC class TrmE-Era-EngA-EngB-Septin-like GTPase superfamily. AIG1/Toc34/Toc159-like paraseptin GTPase family. IAN subfamily.