Year-end Sale % OFF 
Abstract
Author SummaryThe coordination of different cells during pattern formation is a fundamental process in the development of multicellular organisms. In plants, a unique mechanism of directional transport of the signaling molecule auxin between cells demonstrates the importance of cell polarity for tissue patterning. The direction of auxin flow is determined by polar subcellular localization of auxin transport proteins called PINs, which facilitate auxin efflux. At the same time, an auxin-mediated positive feedback mechanism reinforces the polar distribution of PINs. However, the molecular mechanisms that underlie polar PIN localization are not well understood. In eukaryotic cells, the Rho family of small GTPases function as central regulators of cell polarity. We show that a Rho-interacting protein from plants, called ICR1, is required for recruitment via the secretory system of PIN proteins to polar domains in the cell membrane. As a result, ICR1 is required for directional auxin transport and distribution and thereby for proper pattern formation. In addition, both the expression and subcellular localization of ICR1 are regulated by auxin, suggesting that ICR1 could function in a positive feedback loop that reinforces auxin distribution. Thus, ICR1 forms an auxin-modulated link between cell polarity, protein secretion, and auxin-dependent tissue patterning.
Highlights
ROP (Rho of Plants), known as RAC GTPases, have been implicated as master regulators of cell polarity [1,2]
We show that a Rho-interacting protein from plants, called Interactor of Constitutive active ROP 1 (ICR1), is required for recruitment via the secretory system of PIN proteins to polar domains in the cell membrane
Both the expression and subcellular localization of ICR1 are regulated by auxin, suggesting that ICR1 could function in a positive feedback loop that reinforces auxin distribution
Summary
ROP (Rho of Plants), known as RAC GTPases, have been implicated as master regulators of cell polarity [1,2] In their GTPbound, active state, ROPs interact with downstream effector proteins to regulate organization of actin and microtubules (MT), vesicle trafficking, production of phosphoinositides, and gradients of reactive oxygen species (ROS) and Ca2+ [1,2,3,4,5,6]. ROPs are polarly localized and expression of activated dominant ROP mutants that cannot hydrolyze GTP compromises cell polarization [1,2,3,4,5,6] and inhibits endocytic vesicle recycling [3]. Due to their essential role in generation of cell polarity, it was plausible that ROPs regulate distribution of polar cargos including PIN auxin efflux transporters [11]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
