Distribution of RAB5-positive multivesicular endosomes and the trans-Golgi network in root meristematic cells of Arabidopsis thaliana

Abstract

In plant cells, the trans-Golgi network (TGN) is known to act as the early endocytic compartment, whereas RAB5-localizing multivesicular endosomes (MVEs) act as the later compartment. Land plants and certain green algal species possess plant-unique RAB5 homologs (ARA6/RABF1 in Arabidopsis thaliana) in addition to the orthologs of animal RAB5 (RHA1/RABF2a and ARA7/RABF2b in A. thaliana), and these two RAB5 members reside in substantially overlapping but different subpopulations of MVEs. Several studies indicate that the TGN and MVEs are closely related; however, the distribution of the two RAB5 groups in relation to the TGN remains elusive. Here, we quantitatively showed that ARA6 and ARA7 are closely associated with the TGN, and the subpopulation of ARA6 and ARA7 overlaps with the TGN in the root epidermal cells of A. thaliana.