Change in the Actin Cytoskeleton during Seismonastic Movement of Mimosa pudica

Kanzawa, Nobuyuki; Hoshino, Yoshinori; Chiba, Makiko; Hoshino, Daisuke; Kobayashi, Hidetaka; Kamasawa, Naomi; Kishi, Yoshiro; Osumi, Masako; Sameshima, Masazumi; Tsuchiya, Takahide

doi:10.1093/pcp/pcj022

Cited by 48 publications

(47 citation statements)

References 45 publications

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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 pY-actin is present in the amoeboid stage of Acanthamoeba castellanii and is greatly increased in Acanthamoeba cysts (unpublished results), which are biologically analogous to Dictyostelium spores, and tyrosine phosphorylated actin has been reported in the plant Mimosa pudica L., where it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: 85%

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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Section: Discussionmentioning

confidence: 85%

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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“…Tissue sections were prepared as described previously (Kanzawa et al, 2006). Briefly, paraformaldehyde-fixed samples were dehydrated and mounted in a low-melt wax, and sections (15 mm thickness) were rehydrated and used for immunofluorescence analysis.…”

Section: Indirect Immunofluorescence Analysismentioning

confidence: 99%

Purification and Biochemical Characterization of a Novel Ecto-Apyrase, MP67, from Mimosa pudica

et al. 2011

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We have previously reported the presence of an apyrase in Mimosa pudica. However, only limited information is available for this enzyme. Thus, in this study, the apyrase was purified to homogeneity. The purified enzyme had a molecular mass of around 67 kD and was able to hydrolyze both nucleotide triphosphate and nucleotide diphosphate as substrates. The ratio of ATP to ADP hydrolysis velocity of the purified protein was 0.01 in the presence of calcium ion, showing extremely high substrate specificity toward ADP. Thus, we designated this novel apyrase as MP67. A cDNA clone of MP67 was obtained using primers designed from the amino acid sequence of trypsin-digested fragments of the protein. In addition, rapid amplification of cDNA ends-polymerase chain reaction was performed to clone a conventional apyrase (MpAPY2). Comparison of the deduced amino acid sequences showed that MP67 is similar to ecto-apyrases; however, it was distinct from conventional apyrase based on phylogenetic classification. MP67 and MpAPY2 were expressed in Escherichia coli, and the recombinant proteins were purified. The recombinant MP67 showed high substrate specificity toward ADP rather than ATP. A polyclonal antibody raised against the recombinant MP67 was used to examine the tissue distribution and localization of native MP67 in the plant. The results showed that MP67 was ubiquitously distributed in various tissues, most abundantly in leaves, and was localized to plasma membranes. Thus, MP67 is a novel ecto-apyrase with extremely high substrate specificity for ADP.

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“…This assumption is supported by the finding that actin bundles become looser during the rapid turgor movements, seismonastic movements, of Mimosa pudica. 24 In BY-2 cells treated with the proteinacious elicitor, cryptogein, the vacuoles become large and form simple shapes prior to vacuolar rupture and induction of programmed cell death. 25 At vacuolation, the heavily-bundled actin microfilaments transiently appear in the cell cortex despite the actin bundles that run in the transvacuolar strands.…”

Section: Effect Of An Auxin Transport Inhibitor and Auxin On Actin Bumentioning

confidence: 99%

Critical role of actin bundling in plant cell morphogenesis

Higaki

Kojo

Hasezawa

2010

Plant Signaling & Behavior

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Change in the Actin Cytoskeleton during Seismonastic Movement of Mimosa pudica

Cited by 48 publications

References 45 publications

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

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

Purification and Biochemical Characterization of a Novel Ecto-Apyrase, MP67, from Mimosa pudica

Critical role of actin bundling in plant cell morphogenesis

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