Plant Exocytosis, Endocytosis and Membrane Recycling in Turgid Cells

Abstract In plant cells, growth is dependent on cell wall building and plasma membrane growth. Secretion of proteins is vital for cell function and cell–cell communication. The fusion of secretory vesicles at the plasma membrane (exocytosis) is a key mechanism because it delivers proteins and lipids to the plasma membrane and proteins and polysaccharides to the cell wall. The anterograde flow of membranes is balanced by endocytosis, which retrieves excess membrane and recycles plasma membrane receptors and transporters. Exocytosis and endocytosis have recently been shown to underpin the establishment of cell polarity which is key to the control of plant developmental processes. The balance of exocytosis and endocytosis is, therefore, crucial to both plant signalling and development, is highly regulated and is an exciting subject of current research. Key Concepts: Exocytosis is the fusion of secretory vesicles with the plasma membrane. Endocytosis retrieves lipids and proteins from the plasma membrane. The balance of exocytosis and endocytosis regulates cell growth, polarity and expansion, ultimately underpinning all plant developmental processes.