Arabidopsis BRICK1/HSPC300 Is an Essential WAVE-Complex Subunit that Selectively Stabilizes the Arp2/3 Activator SCAR2

Le, Jie; Mallery, Eileen L.; Zhang, Chunhua; Brankle, Steven; Szymanski, Daniel B.

doi:10.1016/j.cub.2006.03.061

Cited by 101 publications

(139 citation statements)

References 42 publications

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“…In support of the former possibility, several studies have shown differential effects between Arp2/3 complex and SCAR/WAVE complex mutants. For example, when compared with Arp2/3 complex mutants, some SCAR/WAVE complex mutants display a less severe reduction in trichome branch length, whilst trichomes of all the mutants display, to a similar extent, abnormally expanded interbranch zones (Basu et al ., 2005; Le et al ., 2006; Zhang et al ., 2008). …”

Section: Discussionmentioning

confidence: 99%

Actin filament reorganisation controlled by the SCAR/WAVE complex mediates stomatal response to darkness

Isner

Costa

et al. 2017

New Phytologist

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Summary Stomata respond to darkness by closing to prevent excessive water loss during the night. Although the reorganisation of actin filaments during stomatal closure is documented, the underlying mechanisms responsible for dark‐induced cytoskeletal arrangement remain largely unknown.We used genetic, physiological and cell biological approaches to show that reorganisation of the actin cytoskeleton is required for dark‐induced stomatal closure.The opal5 mutant does not close in response to darkness but exhibits wild‐type (WT) behaviour when exposed to abscisic acid (ABA) or CaCl2. The mutation was mapped to At5g18410, encoding the PIR/SRA1/KLK subunit of the Arabidopsis SCAR/WAVE complex. Stomata of an independent allele of the PIR gene (Atpir‐1) showed reduced sensitivity to darkness and F1 progenies of the cross between opal5 and Atpir‐1 displayed distorted leaf trichomes, suggesting that the two mutants are allelic. Darkness induced changes in the extent of actin filament bundling in WT. These were abolished in opal5. Disruption of filamentous actin using latrunculin B or cytochalasin D restored wild‐type stomatal sensitivity to darkness in opal5.Our findings suggest that the stomatal response to darkness is mediated by reorganisation of guard cell actin filaments, a process that is finely tuned by the conserved SCAR/WAVE–Arp2/3 actin regulatory module.

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Section: Discussionmentioning

confidence: 99%

Actin filament reorganisation controlled by the SCAR/WAVE complex mediates stomatal response to darkness

Isner

Costa

et al. 2017

New Phytologist

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“…S3), a proposed effector of ROP signaling in the PIN signaling network (Fu et al, 2005) that was placed in an actin-dependent pathway (Table II). To validate the use of LobeFinder as a useful tool to detect lobe number phenotypes, we conducted a similar analysis on the ARP2/3 complex mutant distorted2 (dis2)/arpc2, which has a reported small reduction in lobe number compared with the wild type (El-Din El-Assal et al, 2004;Le et al, 2006). LobeFinder could reveal a significantly reduced lobe number in dis2 (Table II; Supplemental Fig.…”

Section: Genetic Analysis Of the Plasma Membrane-localized Pinsmentioning

confidence: 99%

Reassessing the Roles of PIN Proteins and Anticlinal Microtubules during Pavement Cell Morphogenesis

et al. 2017

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The leaf epidermis is a biomechanical shell that influences the size and shape of the organ. Its morphogenesis is a multiscale process in which nanometer-scale cytoskeletal protein complexes, individual cells, and groups of cells pattern growth and define macroscopic leaf traits. Interdigitated growth of neighboring cells is an evolutionarily conserved developmental strategy. Understanding how signaling pathways and cytoskeletal proteins pattern cell walls during this form of tissue morphogenesis is an important research challenge. The cellular and molecular control of a lobed cell morphology is currently thought to involve PIN-FORMED (PIN)-type plasma membrane efflux carriers that generate subcellular auxin gradients. Auxin gradients were proposed to function across cell boundaries to encode stable offset patterns of cortical microtubules and actin filaments between adjacent cells. Many models suggest that long-lived microtubules along the anticlinal cell wall generate local cell wall heterogeneities that restrict local growth and specify the timing and location of lobe formation. Here, we used Arabidopsis (Arabidopsis thaliana) reverse genetics and multivariate long-term time-lapse imaging to test current cell shape control models. We found that neither PIN proteins nor long-lived microtubules along the anticlinal wall predict the patterns of lobe formation. In fields of lobing cells, anticlinal microtubules are not correlated with cell shape and are unstable at the time scales of cell expansion. Our analyses indicate that anticlinal microtubules have multiple functions in pavement cells and that lobe initiation is likely controlled by complex interactions among cell geometry, cell wall stress patterns, and transient microtubule networks that span the anticlinal and periclinal walls.Plant leaves are thin, mechanically durable organs. Their size and shape influence the efficiency of photosynthetic light capture and strongly influence crop yield (Zhu et al., 2010). The growth properties of the leaf epidermis can influence the morphology of the organ (Savaldi-Goldstein et al., 2007); therefore, there is a strong desire to understand how the division and growth of epidermal cells contribute to polarized growth at the level of tissues and organs. In the plant kingdom, an undulating cell shape is commonly generated in the leaf epidermis as polyhedral cells exit the cell division cycle and undergo an extended phase of polarized expansion (Panteris et al., 1993;Panteris and Galatis, 2005;Andriankaja et al., 2012). Interdigitated growth may give the leaf mechanical stability (Onoda et al., 2015;Sahaf and Sharon, 2016) and/or influence polarized growth at spatial scales that extend beyond that of individual cells (Elsner et al., 2012;Remmler and Rolland-Lagan, 2012).The biomechanics of the lobing process is complex. As in all other plant cell types, turgor pressure provides the driving force for pavement cell morphogenesis, and the physical connectivity of adjacent cells strongly influences the resulting mechanical stre...

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“…In Arabidopsis thaliana, loss of function phenotypes linked to mutations in subunits of the Arp2/3 and the Scar/ Wave complex fall into the distorted group of mutants [Basu et al, 2005;Mathur, 2005;Le et al, 2006]. These mutants are mainly affected in epidermal cell expansion: they develop distorted leaf trichomes and display reduced expansion of leaf pavement and stem hypocotyl epidermal cells.…”

Section: Introductionmentioning

confidence: 99%

The knock‐out of ARP3a gene affects F‐actin cytoskeleton organization altering cellular tip growth, morphology and development in moss Physcomitrella patens

Finka

Saidi

Goloubinoff

et al. 2008

Cell Motil. Cytoskeleton

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The seven subunit Arp2/3 complex is a highly conserved nucleation factor of actin microfilaments. We have isolated the genomic sequence encoding a putative Arp3a protein of the moss Physcomitrella patens. The disruption of this ARP3A gene by allele replacement has generated loss-of-function mutants displaying a complex developmental phenotype. The loss-of function of ARP3A gene results in shortened, almost cubic chloronemal cells displaying affected tip growth and lacking differentiation to caulonemal cells. In moss arp3a mutants, buds differentiate directly from chloronemata to form stunted leafy shoots having differentiated leaves similar to wild type. Yet, rhizoids never differentiate from stem epidermal cells. To characterize the F-actin organization in the arp3a-mutated cells, we disrupted ARP3A gene in the previously described HGT1 strain expressing conditionally the GFP-talin marker. In vivo observation of the F-actin cytoskeleton during P. patens development demonstrated that loss-of-function of Arp3a is associated with the disappearance of specific F-actin cortical structures associated with the establishment of localized cellular growth domains. Finally, we show that constitutive expression of the P. patens Arp3a and its Arabidopsis thaliana orthologs efficiently complement the mutated phenotype indicating a high degree of evolutionary conservation of the Arp3 function in land plants.

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Arabidopsis BRICK1/HSPC300 Is an Essential WAVE-Complex Subunit that Selectively Stabilizes the Arp2/3 Activator SCAR2

Cited by 101 publications

References 42 publications

Actin filament reorganisation controlled by the SCAR/WAVE complex mediates stomatal response to darkness

Actin filament reorganisation controlled by the SCAR/WAVE complex mediates stomatal response to darkness

Reassessing the Roles of PIN Proteins and Anticlinal Microtubules during Pavement Cell Morphogenesis

The knock‐out of ARP3a gene affects F‐actin cytoskeleton organization altering cellular tip growth, morphology and development in moss Physcomitrella patens

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