Coordinated Polar Localization of Auxin Efflux Carrier PIN1 by GNOM ARF GEF

The plant hormone auxin is transported in a polar manner along the shoot-root axis, which requires efflux carriers such as PIN1. Asymmetric localization of PIN1 develops from a random distribution in Arabidopsis early embryogenesis. Coordinated polar localization of PIN1 is defective in gnom embryos. GNON is a membrane-associated guanine-nucleotide exchange factor on ADP-ribosylation factor G protein (ARF GEF). Thus, GNOM-dependent vesicle trafficking may establish cell polarity, resulting in polar auxin transport.
Polar auxin transport has been implicated in a variety of developmental processes, including phototropism, gravitropism, apical dominance, root formation, and vascular tissue patterning (1, 2). These vectorial processes require coordinated [...]