Targeting of auxin carriers to the plasma membrane: effects of monensin on transmembrane auxin transport in Cucurbita pepo L. tissue

Planta ◽  
1994 ◽  
Vol 193 (2) ◽  
Author(s):  
Sally Wilkinson ◽  
DavidA. Morris
Keyword(s):  
Plasma Membrane ◽  
Cucurbita Pepo ◽  
Auxin Transport ◽  
Membrane Effects

scholarly journals LAZY3 plays a pivotal role in positive root gravitropism in Lotus japonicus

2019 ◽  
Vol 71 (1) ◽  
pp. 168-177 ◽  
Author(s):  
Yaping Chen ◽  
Shaoming Xu ◽  
Lu Tian ◽  
Leru Liu ◽  
Mingchao Huang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Auxin Transport ◽  
Positive Root ◽  
Lotus Japonicus ◽  
Polar Auxin Transport ◽  
Pivotal Role ◽  
Root Gravitropism ◽  
Root Stele

LAZY3, polarly localized to the plasma membrane in root stele cells, is involved in rootward polar auxin transport in roots and required for positive root gravitropism in Lotus japonicus.

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

2018 ◽  
Author(s):  
Sander Hille ◽  
Maria Akhmanova ◽  
Matouš Glanc ◽  
Alexander Johnson ◽  
Jiří Friml
Keyword(s):  
Plasma Membrane ◽  
Auxin Transport ◽  
Secretory Vesicle ◽  
Secretory Vesicles ◽  
Transport Mechanisms ◽  
In Planta ◽  
Major Mechanism ◽  
Relative Contribution ◽  
Secretory Transport ◽  
Auxin Flux

Intercellular transport of auxin is driven by PIN-formed (PIN) proteins. 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 it 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-SIM microscopy was used to determine PIN density on the PM. Combing 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 1000x 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 intriguing and theoretically possible model, it unlikely to be a major mechanism of auxin transport in planta.

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