https://www.cell.com/molecular-plant/pdf/S1674-2052(15)00087-8.pdf

Signaling Mechanisms in Pattern-Triggered Immunity (PTI)

https://www.cell.com/cell/pdf/S0092-8674(07)01463-8.pdf

Cytokinesis: placing and making the final cut.

https://www.cell.com/trends/plant-science/pdf/S1360-1385(14)00249-0.pdf

Mitogen-activated protein kinase cascades in signaling plant growth and development.

在自然，植物常常不得不面对病原体攻击。然而，植物疾病很少由于主人植物拥有的有效免疫系统发生。病原体被开始所谓的被触发模式的豁免 PTI 和被触发受动器的豁免 ETI 的二个不同识别系统察觉，哪个被通常排斥病原体攻击的一套导致的辩护伴随。这里，我们讨论表明发生在 PTI 期间的小径的复杂网络，集中于激活 mitogen 的蛋白质 kinases 的参与。

Signaling Mechanisms in Pattern-Triggered Immunity （PTI）

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 PLDα1 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 pldα1cells, 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 pldα1 map65-1 double mutant showed greater sensitivity to salt stress than did either single mutant. These results suggest that PLDα1-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.

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

Cell division depends on the fine control of both microtubule dynamics and microtubule organisation. The microtubule bundling protein MAP65 is a `midzone MAP9 essential for the integrity of the anaphase spindle and cell division. Arabidopsis thaliana MAP65-1 (AtMAP65-1) binds and bundles microtubules by forming 25 nm cross-bridges. Moreover, as AtMAP65-1 bundles microtubules in interphase, anaphase and telophase but does not bind microtubules in prophase or metaphase, its activity through the cell cycle must be under tight control. Here we show that AtMAP65-1 is hyperphosphorylated during prometaphase and metaphase and that CDK and MAPK are involved in this phosphorylation. This phosphorylation inhibits AtMAP65-1 activity. Expression of non-phosphorylatable AtMAP65-1 has a negative effect on mitotic progression resulting in excessive accumulation of microtubules in the metaphase spindle midzone causing a delay in mitosis. We conclude that normal metaphase spindle organisation and the transition to anaphase is dependent on inactivation of AtMAP65-1.

/pdf/control-of-the-atmap65-1-interaction-with-microtubules-4ite6wtb99.pdf

Laci Bögre

Papers

Control of the AtMAP65-1 interaction with microtubules through the cell cycle.