The M3 phosphorylation motif has been functionally conserved for intracellular trafficking of long-looped PIN-FORMEDs in the Arabidopsis root hair cell

BMC Plant Biology

Research Article

Minho Park¹  Hyung-Taeg Cho¹  Anindya Ganguly²  Daisuke Sasayama³ 

[1] Department of Biological Sciences and Plant Genomics and Breeding Institute, Seoul National University, 151-742, Seoul, Korea;Department of Biological Sciences and Plant Genomics and Breeding Institute, Seoul National University, 151-742, Seoul, Korea;Current address, Department of Biology, Washington University, 1 Brookings Drive, 63130, Saint Louis, MO, USA;Department of Biological Sciences and Plant Genomics and Breeding Institute, Seoul National University, 151-742, Seoul, Korea;Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai-cho, Nada-ku, 657-8501, Kobe, Hyogo, Japan;

关键词: Auxin;    Auxin transport;    Hydrophilic loop (of PINs);    Phosphorylation;    PIN-FORMED (PIN);    Protein trafficking;    Root hair;   

DOI  :  10.1186/1471-2229-13-189

 received in 2013-07-31, accepted in 2013-11-21,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundPIN-FORMED (PIN) efflux carriers contribute to polar auxin transport and plant development by exhibiting dynamic and diverse asymmetrical localization patterns in the plasma membrane (PM). Phosphorylation of the central hydrophilic loop (HL) of PINs has been implicated in the regulation of PIN trafficking. Recently, we reported that a phosphorylatable motif (M3) in the PIN3-HL is necessary for the polarity, intracellular trafficking, and biological functions of PIN3. In this study, using the root hair system for PIN activity assay, we investigated whether this motif has been functionally conserved among long-HL PINs.ResultsRoot hair-specific overexpression of wild-type PIN1, 2, or 7 greatly inhibited root hair growth by depleting auxin levels in the root hair cell, whereas overexpression of M3 phosphorylation-defective PIN mutants failed to inhibit root hair growth. Consistent with this root hair phenotype, the PM localization of M3 phosphorylation-defective PIN1 and PIN7 was partially disrupted, resulting in less auxin efflux and restoration of root hair growth. Partial formation of brefeldin A-compartments in these phosphorylation-mutant PIN lines also suggested that their PM targeting was partially disrupted. On the other hand, compared with the PIN1 and PIN7 mutant proteins, M3-phosphorylation-defective PIN2 proteins were almost undetectable. However, the mutant PIN2 protein levels were restored by wortmannin treatment almost to the wild-type PIN2 level, indicating that the M3 motif of PIN2, unlike that of other PINs, is implicated in PIN2 trafficking to the vacuolar lytic pathway.ConclusionsThese results suggest that the M3 phosphorylation motif has been functionally conserved to modulate the intracellular trafficking of long-HL PINs, but its specific function in trafficking has diverged among PIN members.

【 授权许可】

Unknown   
© Sasayama et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.