scholarly journals A Sec14p-nodulin domain phosphatidylinositol transfer protein polarizes membrane growth of Arabidopsis thaliana root hairs

2005 ◽  
Vol 168 (5) ◽  
pp. 801-812 ◽  
Author(s):  
Patrick Vincent ◽  
Michael Chua ◽  
Fabien Nogue ◽  
Ashley Fairbrother ◽  
Hal Mekeel ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Plasma Membrane ◽  
Membrane Trafficking ◽  
Root Hair ◽  
Root Hairs ◽  
Extracellular Milieu ◽  
Root Hair Development ◽  
Gene Ablation ◽  
Membrane Growth ◽  
Phosphatidylinositol Transfer

Phosphatidylinositol (PtdIns) transfer proteins (PITPs) regulate signaling interfaces between lipid metabolism and membrane trafficking. Herein, we demonstrate that AtSfh1p, a member of a large and uncharacterized Arabidopsis thaliana Sec14p-nodulin domain family, is a PITP that regulates a specific stage in root hair development. AtSfh1p localizes along the root hair plasma membrane and is enriched in discrete plasma membrane domains and in the root hair tip cytoplasm. This localization pattern recapitulates that visualized for PtdIns(4,5)P2 in developing root hairs. Gene ablation experiments show AtSfh1p nullizygosity compromises polarized root hair expansion in a manner that coincides with loss of tip-directed PtdIns(4,5)P2, dispersal of secretory vesicles from the tip cytoplasm, loss of the tip f-actin network, and manifest disorganization of the root hair microtubule cytoskeleton. Derangement of tip-directed Ca2+ gradients is also apparent and results from isotropic influx of Ca2+ from the extracellular milieu. We propose AtSfh1p regulates intracellular and plasma membrane phosphoinositide polarity landmarks that focus membrane trafficking, Ca2+ signaling, and cytoskeleton functions to the growing root hair apex. We further suggest that Sec14p-nodulin domain proteins represent a family of regulators of polarized membrane growth in plants.

scholarly journals The BEACH Domain-Containing Protein SPIRRIG Modulates Actin-Dependent Root Hair Development in Coordination with the WAVE/SCAR and ARP2/3 Complexes

2020 ◽  
Author(s):  
Sabrina Chin ◽  
Taegun Kwon ◽  
Bibi Rafeiza Khan ◽  
J. Alan Sparks ◽  
Eileen L. Mallery ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Root Hair ◽  
Tip Growth ◽  
Developmental Stages ◽  
Root Hairs ◽  
Filamentous Actin ◽  
Root Hair Development ◽  
Live Cell Microscopy ◽  
Hair Development ◽  
Cellular Components

AbstractRoot hairs are single cell protrusions that enable roots to optimize nutrient and water acquisition. They attain their tubular shapes by confining growth to the cell apex, a process called tip growth. The actin cytoskeleton and endomembrane system are essential for tip growth; however, little is known about how these cellular components coordinate their activities during this process. Here, we show that SPIRRIG (SPI), a BEACH domain-containing protein involved in membrane trafficking, and BRK1 and SCAR2, subunits of the WAVE/SCAR (W/SCR) and actin related protein (ARP)2/3 activation complexes, display polarized localizations to root hairs at distinct developmental stages. SPI accumulates at the root hair apex via post-Golgi vesicles and positively regulates tip growth by maintaining tip-focused vesicle secretion and filamentous-actin integrity. BRK1 and SCAR2 on the other hand, mark the root hair initiation domain to specify the position of root hair emergence. Live cell microscopy revealed that BRK1 depletion coincided with SPI accumulation as root hairs transitioned from initiation to tip growth. Furthermore, double mutant studies showed that SPI genetically interacts with BRK1 and ARP2/3. Taken together, our work uncovers a role for SPI in facilitating actin-dependent root hair development through pathways that intersect with the W/SCR and ARP2/3 complexes.

Spatial and temporal localization of SPIRRIG and WAVE/SCAR reveal roles for these proteins in actin-mediated root hair development

2021 ◽  
Author(s):  
Sabrina Chin ◽  
Taegun Kwon ◽  
Bibi Rafeiza Khan ◽  
J Alan Sparks ◽  
Eileen L Mallery ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Root Hair ◽  
Tip Growth ◽  
Developmental Stages ◽  
Root Hairs ◽  
Filamentous Actin ◽  
Root Hair Development ◽  
Hair Development ◽  
Temporal Localization ◽  
Cellular Components

Abstract Root hairs are single cell protrusions that enable roots to optimize nutrient and water acquisition. These structures attain their tubular shapes by confining growth to the cell apex, a process called tip growth. The actin cytoskeleton and endomembrane systems are essential for tip growth; however, little is known about how these cellular components coordinate their activities during this process. Here, we show that SPIRRIG (SPI), a BEACH domain-containing protein involved in membrane trafficking, and BRK1 and SCAR2, subunits of the WAVE/SCAR (W/SC) actin nucleating promoting complex, display polarized localizations in Arabidopsis thaliana root hairs during distinct developmental stages. SPI accumulates at the root hair apex via post-Golgi compartments and positively regulates tip growth by maintaining tip-focused vesicle secretion and filamentous-actin integrity. BRK1 and SCAR2 on the other hand, mark the root hair initiation domain to specify the position of root hair emergence. Consistent with the localization data, tip growth was reduced in spi and the position of root hair emergence was disrupted in brk1 and scar1234. BRK1 depletion coincided with SPI accumulation as root hairs transitioned from initiation to tip growth. Taken together, our work uncovers a role for SPI in facilitating actin-dependent root hair development in Arabidopsis through pathways that might intersect with W/SC.

scholarly journals Inhibition of Pre-mRNA Splicing Promotes Root Hair Development in Arabidopsis thaliana

2019 ◽  
Vol 60 (9) ◽  
pp. 1974-1985 ◽  
Author(s):  
Miku Ishizawa ◽  
Kayo Hashimoto ◽  
Misato Ohtani ◽  
Ryosuke Sano ◽  
Yukio Kurihara ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Hair ◽  
Protein A ◽  
Root Hairs ◽  
Carbon Dioxide Concentration ◽  
Light Response ◽  
Mrna Splicing ◽  
Gene Encoding ◽  
Root Hair Development ◽  
Hair Development

Abstract Root hairs protruding from epidermal cells increase the surface area for water absorption and nutrient uptake. Various environmental factors including light, oxygen concentration, carbon dioxide concentration, calcium and mycorrhizal associations promote root hair formation in Arabidopsis thaliana. Light regulates the expression of a large number of genes at the transcriptional and post-transcriptional levels; however, there is little information linking the light response to root hair development. In this study, we describe a novel mutant, light-sensitive root-hair development 1 (lrh1), that displays enhanced root hair development in response to light. Hypocotyl and root elongation was inhibited in the lrh1 mutant, which had a late flowering phenotype. We identified the gene encoding the p14 protein, a putative component of the splicing factor 3b complex essential for pre-mRNA splicing, as being responsible for the lrh1 phenotype. Indeed, regulation of alternative splicing was affected in lrh1 mutants and treatment with a splicing inhibitor mimicked the lrh1 phenotype. Genome-wide alterations in pre-mRNA splicing patterns including differential splicing events of light signaling- and circadian clock-related genes were found in lrh1 as well as a difference in transcriptional regulation of multiple genes including upregulation of essential genes for root hair development. These results suggest that pre-mRNA splicing is the key mechanism regulating root hair development in response to light signals.

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