Microtubules, MAPs and plant directional cell expansion

Sedbrook, John C.; Kaloriti, Despina

doi:10.1016/j.tplants.2008.04.002

Cited by 124 publications

(102 citation statements)

References 67 publications

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“…The phosphorylation by MAPK regulates both the binding of MAP65-1 to microtubules and its targeting to the midzone, thereby affecting mitosis (Smertenko et al, 2006). Mutations in MAPs or MAPKs lead to a wide range of cellular phenotypes related to growth, such as branching of root hairs and swelling of diffusely growing epidermal cells (Lucas and Shaw, 2008;Sedbrook and Kaloriti, 2008). However, little is known about how microtubules are regulated in response to salt stress.…”

Section: Introductionmentioning

confidence: 99%

Phosphatidic Acid Regulates Microtubule Organization by Interacting with MAP65-1 in Response to Salt Stress in Arabidopsis

et al. 2012

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Membrane lipids play fundamental structural and regulatory roles in cell metabolism and signaling. Here, we report that phosphatidic acid (PA), a product of phospholipase D (PLD), regulates MAP65-1, a microtubule-associated protein, in response to salt stress. Knockout of the PLDa1 gene resulted in greater NaCl-induced disorganization of microtubules, which could not be recovered during or after removal of the stress. Salt affected the association of MAP65-1 with microtubules, leading to microtubule disorganization in plda1cells, which was alleviated by exogenous PA. PA bound to MAP65-1, increasing its activity in enhancing microtubule polymerization and bundling. Overexpression of MAP65-1 improved salt tolerance of Arabidopsis thaliana cells. Mutations of eight amino acids in MAP65-1 led to the loss of its binding to PA, microtubule-bundling activity, and promotion of salt tolerance. The plda1 map65-1 double mutant showed greater sensitivity to salt stress than did either single mutant. These results suggest that PLDa1-derived PA binds to MAP65-1, thus mediating microtubule stabilization and salt tolerance. The identification of MAP65-1 as a target of PA reveals a functional connection between membrane lipids and the cytoskeleton in environmental stress signaling.

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Section: Introductionmentioning

confidence: 99%

Phosphatidic Acid Regulates Microtubule Organization by Interacting with MAP65-1 in Response to Salt Stress in Arabidopsis

et al. 2012

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“…In elongating cells, such as those found in roots and etiolated hypocotyls, cortical MTs become arranged parallel to each other and transverse to the longitudinal axis of the cell (Sedbrook and Kaloriti, 2008). This organization guides the positioning and trajectories of cellulose synthase complexes as they are delivered to the plasma membrane and deposit cellulose microfibrils around the cell circumference (Baskin, 2001;Paredez et al, 2006Paredez et al, , 2008Crowell et al, 2009Crowell et al, , 2010Gutierrez et al, 2009;Chan et al, 2010Chan et al, , 2011Chen et al, 2010;Lloyd, 2011;Fujita et al, 2011Fujita et al, , 2012.…”

Section: Introductionmentioning

confidence: 99%

The Microtubule Plus-End Tracking Proteins SPR1 and EB1b Interact to Maintain Polar Cell Elongation and Directional Organ Growth in Arabidopsis

et al. 2014

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The microtubule plus-end tracking proteins (+TIPs) END BINDING1b (EB1b) and SPIRAL1 (SPR1) are required for normal cell expansion and organ growth. EB proteins are viewed as central regulators of +TIPs and cell polarity in animals; SPR1 homologs are specific to plants. To explore if EB1b and SPR1 fundamentally function together, we combined genetic, biochemical, and cell imaging approaches in Arabidopsis thaliana. We found that eb1b-2 spr1-6 double mutant roots exhibit substantially more severe polar expansion defects than either single mutant, undergoing right-looping growth and severe axial twisting instead of waving on tilted hard-agar surfaces. Protein interaction assays revealed that EB1b and SPR1 bind each other and tubulin heterodimers, which is suggestive of a microtubule loading mechanism. EB1b and SPR1 show antagonistic association with microtubules in vitro. Surprisingly, our combined analyses revealed that SPR1 can load onto microtubules and function independently of EB1 proteins, setting SPR1 apart from most studied +TIPs in animals and fungi. Moreover, we found that the severity of defects in microtubule dynamics in spr1 eb1b mutant hypocotyl cells correlated well with the severity of growth defects. These data indicate that SPR1 and EB1b have complex interactions as they load onto microtubule plus ends and direct polar cell expansion and organ growth in response to directional cues.

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“…Cortical microtubules control cell growth by orientating cellulose fibrils and cellulose fibril arrays and build the mechanical properties of the cell wall (Paredez et al, 2006;Somerville, 2006;Kaloriti et al, 2007;Lloyd and Chan, 2008;Sedbrook and Kaloriti, 2008;Lloyd, 2011). The clockwise and counterclockwise rotations of cortical microtubules are dynamic features in growing hypocotyl cells as observed via longterm time-lapse imaging (Chan et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Arabidopsis MICROTUBULE DESTABILIZING PROTEIN40 Is Involved in Brassinosteroid Regulation of Hypocotyl Elongation

et al. 2012

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The brassinosteroid (BR) phytohormones play crucial roles in regulating plant cell growth and morphogenesis, particularly in hypocotyl cell elongation. The microtubule cytoskeleton is also known to participate in the regulation of hypocotyl elongation. However, it is unclear if BR regulation of hypocotyl elongation involves the microtubule cytoskeleton. In this study, we demonstrate that BRs mediate hypocotyl cell elongation by influencing the orientation and stability of cortical microtubules. Further analysis identified the previously undiscovered Arabidopsis thaliana MICROTUBULE DESTABILIZING PROTEIN40 (MDP40) as a positive regulator of hypocotyl cell elongation. BRASSINAZOLE-RESISTANT1, a key transcription factor in the BR signaling pathway, directly targets and upregulates MDP40. Overexpression of MDP40 partially rescued the shorter hypocotyl phenotype in BR-deficient mutant de-etiolated-2 seedlings. Reorientation of the cortical microtubules in the cells of MDP40 RNA interference transgenic lines was less sensitive to BR. These findings demonstrate that MDP40 is a key regulator in BR regulation of cortical microtubule reorientation and mediates hypocotyl growth. This study reveals a mechanism involving BR regulation of microtubules through MDP40 to mediate hypocotyl cell elongation.

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Microtubules, MAPs and plant directional cell expansion

Cited by 124 publications

References 67 publications

Phosphatidic Acid Regulates Microtubule Organization by Interacting with MAP65-1 in Response to Salt Stress in Arabidopsis

Phosphatidic Acid Regulates Microtubule Organization by Interacting with MAP65-1 in Response to Salt Stress in Arabidopsis

The Microtubule Plus-End Tracking Proteins SPR1 and EB1b Interact to Maintain Polar Cell Elongation and Directional Organ Growth in Arabidopsis

Arabidopsis MICROTUBULE DESTABILIZING PROTEIN40 Is Involved in Brassinosteroid Regulation of Hypocotyl Elongation

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