Multifunctionality of Vesicle-Associated Membrane Protein 721 and 722 in Plants

Since first identified as components of an immune exocytic pathway, studies on vesicle-associated membrane protein 721 and 722 (VAMP721/722) have revealed that these proteins in plants are more versatile than expected, as they are also involved in cell division, growth, development and abiotic stress responses. The lethality of vamp721 vamp722 double mutant and the directed movement of VAMP722 vesicles to infected sites, otherwise randomly scattered, in GFP-VAMP722-expressing Arabidopsis strongly suggest that VAMP721/722 engaged in a default secretory pathway have been co-opted for a variety of stress responses. Therefore, we here review the current understanding of VAMP721/722 functions and discuss how their diverse biological activities can be regulated.