Updated project metadata. In Arabidopsis and presumably other flowering plant species as well, there are two non-conserved putative ARF GTPases in addition to the eukaryotically conserved ARF1 (class I) and eight ARF guanine-nucleotide exchange factors (ARF-GEFs) that appear to be involved in specific membrane-trafficking pathways. The aim of the study is to analyze which of the ARFs is activated by which ARF-GEF.