The proteins encoded by either the wild-type Ubi::ZmDMP-eGFP (Ubi, ubiquitin; eGFP , enhanced green fluorescent protein) (CAUHOI) or mutant Ubi::zmdmp-eGFP (CAU5) colocalized with the plasma membrane marker AtPIP2a-mCherry in maize protoplasts (Fig. 4e,f),