Next Article in Journal
Impact of Machine Perfusion on Biliary Complications after Liver Transplantation
Next Article in Special Issue
Auxin Controlled by Ethylene Steers Root Development
Previous Article in Journal
Regulation of Leptin Methylation Not via Apoptosis by Melatonin in the Rescue of Chronic Programming Liver Steatosis
Previous Article in Special Issue
Advances in Understanding the Mechanism of Action of the Auxin Permease AUX1
Open AccessArticle

Relative Contribution of PIN-Containing Secretory Vesicles and Plasma Membrane PINs to the Directed Auxin Transport: Theoretical Estimation

1
Mathematical Institute, Faculty of Science, Leiden University, 2333 CA Leiden, The Netherlands
2
Institute of Science and Technology (IST) Austria, Am Campus 1, 3400 Klosterneuburg, Austria
3
Department Experimental Plant Biology, Faculty of Science, Charles University, 12843 Prague, Czech Republic
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Int. J. Mol. Sci. 2018, 19(11), 3566; https://doi.org/10.3390/ijms19113566
Received: 17 September 2018 / Revised: 2 November 2018 / Accepted: 4 November 2018 / Published: 12 November 2018
(This article belongs to the Special Issue Auxins and Cytokinins in Plant Development)
The intercellular transport of auxin is driven by PIN-formed (PIN) auxin efflux carriers. PINs are localized at the plasma membrane (PM) and on constitutively recycling endomembrane vesicles. Therefore, PINs can mediate auxin transport either by direct translocation across the PM or by pumping auxin into secretory vesicles (SVs), leading to its secretory release upon fusion with the PM. Which of these two mechanisms dominates is a matter of debate. Here, we addressed the issue with a mathematical modeling approach. We demonstrate that the efficiency of secretory transport depends on SV size, half-life of PINs on the PM, pH, exocytosis frequency and PIN density. 3D structured illumination microscopy (SIM) was used to determine PIN density on the PM. Combining this data with published values of the other parameters, we show that the transport activity of PINs in SVs would have to be at least 1000× greater than on the PM in order to produce a comparable macroscopic auxin transport. If both transport mechanisms operated simultaneously and PINs were equally active on SVs and PM, the contribution of secretion to the total auxin flux would be negligible. In conclusion, while secretory vesicle-mediated transport of auxin is an intriguing and theoretically possible model, it is unlikely to be a major mechanism of auxin transport in planta. View Full-Text
Keywords: auxin; polar auxin transport; PIN transporters; secretion; 3D-SIM microscopy; mathematical modeling auxin; polar auxin transport; PIN transporters; secretion; 3D-SIM microscopy; mathematical modeling
Show Figures

Figure 1

MDPI and ACS Style

Hille, S.; Akhmanova, M.; Glanc, M.; Johnson, A.; Friml, J. Relative Contribution of PIN-Containing Secretory Vesicles and Plasma Membrane PINs to the Directed Auxin Transport: Theoretical Estimation. Int. J. Mol. Sci. 2018, 19, 3566.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop