Gamma-secretase is a multisubunit complex with intramembrane proteolytic 
activity. In humans it was identified in genetic screens of patients suffering 
from familial forms of Alzheimer's disease, and since then it was shown to 
mediate cleavage of more than 80 substrates, including amyloid precursor protein 
or Notch receptor. Moreover, in animals, γ-secretase was shown to be involved in 
regulation of a wide range of cellular events, including cell signalling, 
regulation of endocytosis of membrane proteins, their trafficking, and 
degradation. Here we show that genes coding for γ-secretase homologues are 
present in plant genomes. Also, amino acid motifs crucial for γ-secretase 
activity are conserved in plants. Moreover, all γ-secretase subunits: PS1/PS2, 
APH-1, PEN-2, and NCT colocalize and interact with each other in Arabidopsis 
thaliana protoplasts. The intracellular localization of γ-secretase subunits in 
Arabidopsis protoplasts revealed a distribution in endomembrane system 
compartments that is consistent with data from animal studies. Together, our 
data may be considered as a starting point for analysis of γ-secretase in 
plants.