Roles of Membrane Trafficking and Receptor-Kinase Signaling in Plant Development
Plants rely on signaling pathways to coordinate their growth and development as well as elaborate mechanisms to control the movements of proteins within their cells. Key regulators of protein movement in plant and animal cells include members of the ADP-ribosylation factor GTPase activating protein (ARF GAP) family which promote efficient loading of protein cargo into membrane-bound vesicles. Studies of an Arabidopsis ARF GAP, NEVERSHED (NEV), have revealed an essential role for regulating protein movement during the programmed process of cell separation that leads to flower abscission. A sensitized genetic screen has led to the identification of a set of three receptor-like kinases, EVERSHED (EVR), SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE1 (SERK1), and CAST AWAY (CST), that function to prevent abscission. The primary focus of this project is to characterize the roles of the EVR, SERK1, and CST receptor-like kinases as temporal and spatial inhibitors of organ separation, and to determine whether they control abscission by regulating the localization or activity of other receptor-like kinases known to activate abscission. The secondary objective of this project is to analyze the functions of NEV and another closely-related ARF GAP during cell expansion and plant growth. A combination of molecular, genetic, biochemical and cell biological approaches will be used to carry out these research objectives. The expected results are that both the timing and extent of the loss of cell adhesion in plants are tightly controlled by complex interactions between receptor-like kinases. This research is likely to provide novel insights into how abscission could be controlled in crop plants and has the potential to enhance our understanding of fundamental questions in plant biology such as how the availability of the transmembrane receptors that activate diverse signaling pathways is regulated.
