Research Advances of Adaptor Protein AP Complexes in Plants

Membrane protein trafficking is one of the most important events of eukaryotic cells, which plays a crucial role in cellular processes such as cell division, differentiation, growth, extracellular nutrient absorption, intracellular signal transduction, and stress defense. Membrane protein transport mainly involves vesicular trafficking pathways including endocytosis, exocytosis, and vacuolar/lysosomal degradation. Adaptor proteins (APs) play an important regulatory role in vesicular trafficking processes such as recognition of membrane receptor proteins, cargo sorting, recruitment and assembly of clathrin, and recruitment of accessory proteins. Currently, five AP complexes have been identified in eukaryotic organisms, namely AP-1, AP-2, AP-3, AP-4, and AP-5. This article mainly reviews the composition, structure, subcellular localization, and biological functions of the plant AP complexes based on the research progress of animal and yeast cell AP. We also discuss outstanding questions about potential function of AP complex and present future perspectives in plants.