 However, even the modified form of NpHR showed poor localization at the cell membrane.To achieve higher membrane-localization it was further modified by addition of a golgi export signal and membrane trafficking signal from a potassium channel (Kir2.1).The addition of Kir2.1 signal significantly improved the membrane localization of NpHR and this engineered form of NpHR was labeled eNpHR3.0 

Halorhodopsin is used in optogenetics to hyperpolarize (or inhibit) specific neurons.