Tyrosine phosphorylation in plant bending

Kameyama, Kazuhisa; Kishi, Yoshiro; Yoshimura, Masanori; Kanzawa, Nobuyuki; Sameshima, Masazumi; Tsuchiya, Takahide

doi:10.1038/35024149

Cited by 131 publications

(96 citation statements)

References 10 publications

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“…Taninos intervêm na estocagem e liberação de íons, especialmente do cálcio, o qual está envolvido na agregação dos componentes do citoesqueleto, particularmente dos microfilamentos de actina em células motoras (Toriyama & Satô 1971;FleuratLessard & Millet 1984;Fleurat-Lessard 1988;Kameyama et al 2000;Yamashiro et al 2001).…”

Section: Discussionunclassified

Anatomia comparada do pulvino, pecíolo e raque de Pterodon pubescens Benth. (Fabaceae - Faboideae)

Rodrigues¹,

Machado

2004

Acta Bot. Bras.

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RESUMO -(Anatomia comparada do pulvino, pecíolo e raque de Pterodon pubescens Benth. (Fabaceae -Faboideae)). Em Pterodon pubescens, os pulvinos primário e secundário, órgãos responsáveis pelos movimentos foliares, apresentam peculiaridades estruturais em relação ao pecíolo e raque. Estas peculiaridades incluem cutícula mais espessa, córtex mais desenvolvido formado por células parenquimáticas de formas variáveis, sistema vascular em posição central, floema circundado por fibras septadas não lignificadas e medula parenquimática reduzida ou ausente. Pecíolo e raque apresentam córtex reduzido constituído por células parenquimáticas isodiamétricas, sistema vascular periférico, floema envolvido por calota de fibras gelatinosas e medula ampla. Compostos fenólicos foram detectados no vacúolo das células corticais dos pulvinos, enquanto que no córtex e medula do pecíolo e da raque foram observados amiloplastos em abundância e ausência de compostos fenólicos. Em geral, as características estruturais do pulvino de P. pubescens são comuns aos pulvinos das demais espécies de Fabaceae e têm sido relacionadas com a intensificação de trocas laterais de íons e água entre células do córtex e sistema vascular, além de proporcionar maior flexibilidade e capacidade de movimento desta região. Já as características do pecíolo e da raque conferem maior rigidez a estas estruturas foliares. Palavras-chave: anatomia, pecíolo, Pterodon pubescens, pulvino, raque ABSTRACT -(Comparative anatomy of pulvinus, petiole and rachis of Pterodon pubescens Benth. (Fabaceae -Faboideae)). InPterodon pubescens the primary and secondary pulvini show structural peculiarities in relations of petiole and rachis. These peculiarities include thicker cuticule, more developed cortex with only parenchyma cells with irregular shape, central vascular tissues, presence of septate fibers around the phloem, and absent or reduced pith. Petiole and rachis show reduced cortex constituted by parenchyma isodiameters cells, peripheric vascular tissues surrounded by gelatinous fibers and pith. Phenolic compounds were detected inside vacuole of parenchyma cells of the pulvinus. Starch grains were observed in the parenchyma cells of petiole and rachis. The features of P. pubescens pulvinus are common to pulvini of others species of Fabaceae, and have been associated to the intensification of lateral changes of ion and water between cortical cells and vascular tissues, besides to provide more flexibility and movement capacity of this organ. On the other hand, the features of petiole and rachis give more rigidity to these leaves structures.

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Section: Discussionunclassified

Anatomia comparada do pulvino, pecíolo e raque de Pterodon pubescens Benth. (Fabaceae - Faboideae)

Rodrigues¹,

Machado

2004

Acta Bot. Bras.

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“…Thus far, we have found no evidence for pY-actin in mammalian cells (HeLa, Cos7, NIH 3T3, HEK293), even when exposed to stress or addition of PAO. pY-actin is present in the amoeboid stage of Acanthamoeba castellanii and is greatly increased in Acanthamoeba cysts (unpublished results), which are biologically analogous to Dictyostelium spores, and tyrosine phosphorylated actin has been reported in the plant Mimosa pudica L., where it seems to inhibit the bending of petioles that occurs upon contact (30,31).…”

Section: Discussionmentioning

confidence: 99%

Phosphorylation of actin Tyr-53 inhibits filament nucleation and elongation and destabilizes filaments

Liu¹,

Shu²,

Hong³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Dictyostelium actin was shown to become phosphorylated on Tyr-53 late in the developmental cycle and when cells in the amoeboid stage are subjected to stress but the phosphorylated actin had not been purified and characterized. We have separated phosphorylated and unphosphorylated actin and shown that Tyr-53 phosphorylation substantially reduces actin's ability to inactivate DNase I, increases actin's critical concentration, and greatly reduces its rate of polymerization. Tyr-53 phosphorylation substantially, if not completely, inhibits nucleation and elongation from the pointed end of actin filaments and reduces the rate of elongation from the barbed end. Negatively stained electron microscopic images of polymerized Tyr-53-phosphorylated actin show a variable mixture of small oligomers and filaments, which are converted to more typical, long filaments upon addition of myosin subfragment 1. Tyr-53-phosphorylated and unphosphorylated actin copolymerize in vitro, and phosphorylated and unphosphorylated actin colocalize in amoebae. Tyr-53 phosphorylation does not affect the ability of filamentous actin to activate myosin ATPase.actin polymerization ͉ Dictyostelium ͉ phosphorylated actin T ransfer of Dictyostelium amoebae from nutrient to nonnutrient medium initiates a 24-hour developmental cycle (1) in which the amoebae aggregate and differentiate to form multicellular organisms that mature to fruiting bodies containing stable spores from which, when they are placed in nutrient medium, amoebae germinate. Several laboratories (2-4) reported tyrosine phosphorylation of actin [phosphotyrosine actin (pY-actin)] correlated with rearrangements of the actin cytoskeleton during the developmental cycle. pY-actin appears late in maturing spores, i.e., Ϸ24 h into the developmental cycle, reaches a maximum level at Ϸ36 h, at which time Ϸ50% of the actin is phosphorylated (3), remains constant for Ϸ20 days, at 22°C, and then decreases, disappearing entirely by 30 days, at which time the spores are no longer viable (3). When viable spores are placed in nutrient medium, pY-actin is dephosphorylated, with a half-life of Ϸ5 min (3), before spore swelling and germination (2, 4).Although vegetative amoebae in nutrient medium contain little or no pY-actin (5, 6), phosphorylation transiently increases (for Ϸ20-25 min) when amoebae are transferred from nonnutrient to nutrient medium (7), with concurrent changes in cell shape, for example, loss of pseudopods, rounding up of the previously elongated cells, and weakened adherence to the substratum (7). Tyrosine phosphorylation also occurs when vegetative amoebae in nutrient medium are exposed to phenylarsine oxide (PAO) (5), an inhibitor of phosphotyrosine phosphatase, or are subjected to stress, for example, inhibition of oxidative phosphorylation (8, 9) or elevated temperature (9), with parallel changes in cell shape similar to the changes that occur when cells are transferred from nonnutrient to nutrient medium.Importantly, phosphorylation occurs uniquely at Tyr-53 (9). Thus, phosphoryl...

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“…Actin is also one of the proteins found to be tyrosine phosphorylated in fibroblasts expressing constitutively active Src tyrosine kinase and displaying significant cytoskeleton rearrangement (4). In Mimosa pudica, a plant that closes its leaves and droops its petioles when touched, actin is heavily tyrosine phosphorylated, and a decrease in actin phosphorylation correlates with petiole bending (5). In none of these examples, however, is the precise connection between actin phosphorylation and cytoskeleton remodeling well understood.…”

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confidence: 99%

Modulation of actin structure and function by phosphorylation of Tyr-53 and profilin binding

Baek

Xiong

Ferrón

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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On starvation, Dictyostelium cells aggregate to form multicellular fruiting bodies containing spores that germinate when transferred to nutrient-rich medium. This developmental cycle correlates with the extent of actin phosphorylation at Tyr-53 (pY53-actin), which is low in vegetative cells but high in viable mature spores. Here we describe high-resolution crystal structures of pY53-actin and unphosphorylated actin in complexes with gelsolin segment 1 and profilin. In the structure of pY53-actin, the phosphate group on Tyr-53 makes hydrogen-bonding interactions with residues of the DNase I-binding loop (D-loop) of actin, resulting in a more stable conformation of the D-loop than in the unphosphorylated structures. A more rigidly folded D-loop may explain some of the previously described properties of pY53-actin, including its increased critical concentration for polymerization, reduced rates of nucleation and pointed end elongation, and weak affinity for DNase I. We show here that phosphorylation of Tyr-53 inhibits subtilisin cleavage of the D-loop and reduces the rate of nucleotide exchange on actin. The structure of profilin-Dictyostelium-actin is strikingly similar to previously determined structures of profilin-␤-actin and profilin-␣-actin. By comparing this representative set of profilin-actin structures with other structures of actin, we highlight the effects of profilin on the actin conformation. In the profilin-actin complexes, subdomains 1 and 3 of actin close around profilin, producing a 4.7°rotation of the two major domains of actin relative to each other. As a result, the nucleotide cleft becomes moderately more open in the profilin-actin complex, probably explaining the stimulation of nucleotide exchange on actin by profilin.actin phosphorylation ͉ profilin-actin structure ͉ pY53-actin structure ͉ Dictyostelium discoideum actin ͉ gelsolin-actin structure

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Tyrosine phosphorylation in plant bending

Cited by 131 publications

References 10 publications

Anatomia comparada do pulvino, pecíolo e raque de Pterodon pubescens Benth. (Fabaceae - Faboideae)

Anatomia comparada do pulvino, pecíolo e raque de Pterodon pubescens Benth. (Fabaceae - Faboideae)

Phosphorylation of actin Tyr-53 inhibits filament nucleation and elongation and destabilizes filaments

Modulation of actin structure and function by phosphorylation of Tyr-53 and profilin binding

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