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Myosin-Powered Membrane Compartment Drives Cytoplasmic Streaming, Cell Expansion and Plant Development.

Peremyslov VV, Cole RA, Fowler JE, Dolja VV - PLoS ONE (2015)

Bottom Line: Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics.Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming.It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, United States of America.

ABSTRACT
Using genetic approaches, particle image velocimetry and an inert tracer of cytoplasmic streaming, we have made a mechanistic connection between the motor proteins (myosins XI), cargo transported by these motors (distinct endomembrane compartment defined by membrane-anchored MyoB receptors) and the process of cytoplasmic streaming in plant cells. It is shown that the MyoB compartment in Nicotiana benthamiana is highly dynamic moving with the mean velocity of ~3 μm/sec. In contrast, Golgi, mitochondria, peroxisomes, carrier vesicles and a cytosol flow tracer share distinct velocity profile with mean velocities of 0.6-1.5 μm/sec. Dominant negative inhibition of the myosins XI or MyoB receptors using overexpression of the N. benthamiana myosin cargo-binding domain or MyoB myosin-binding domain, respectively, resulted in velocity reduction for not only the MyoB compartment, but also each of the tested organelles, vesicles and cytoplasmic streaming. Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics. Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming. It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering. These results support a model according to which myosin-dependent, MyoB receptor-mediated transport of a specialized membrane compartment that is conserved in all land plants drives cytoplasmic streaming that carries organelles and vesicles and facilitates cell growth and plant development.

No MeSH data available.


Related in: MedlinePlus

Dominant negative inhibition of particulate trafficking in N. benthamiana leaf epidermal cells upon transient overexpression of β-glucuronidase (GUS; control), the globular tail domain of N. benthamiana myosin XI-K (XI-K GTD) and the myosin-binding DUF593 domains of N. benthamiana MyoB1 and MyoB2 (MyoB1 DUF593 and MyoB2 DUF593).The mean velocities (μm/sec) and standard deviations are shown for MyoB1 compartment tagged by full-size N. benthamiana MyoB1-GFP (A), Golgi stacks (B), mitochondria (C), peroxisomes (D), vesicles tagged by mCherry:VAMP721 (E) and inclusion bodies formed by the C-terminal fragment of mCherry-tagged, viral proteinμNS, mCherry-μNS (F). Percent of the mean velocity reduction relative to GUS control is shown below each column.
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pone.0139331.g001: Dominant negative inhibition of particulate trafficking in N. benthamiana leaf epidermal cells upon transient overexpression of β-glucuronidase (GUS; control), the globular tail domain of N. benthamiana myosin XI-K (XI-K GTD) and the myosin-binding DUF593 domains of N. benthamiana MyoB1 and MyoB2 (MyoB1 DUF593 and MyoB2 DUF593).The mean velocities (μm/sec) and standard deviations are shown for MyoB1 compartment tagged by full-size N. benthamiana MyoB1-GFP (A), Golgi stacks (B), mitochondria (C), peroxisomes (D), vesicles tagged by mCherry:VAMP721 (E) and inclusion bodies formed by the C-terminal fragment of mCherry-tagged, viral proteinμNS, mCherry-μNS (F). Percent of the mean velocity reduction relative to GUS control is shown below each column.

Mentions: The overexpression of the cargo binding, globular tail domain of N. benthamiana myosin XI-K (GTD-K:HA3) was used as a positive control in all dominant negative inhibition experiments because this domain has a strong inhibitory effect on myosin-dependent transport [22]. The bacterial β-glucuronidase (GUS:HA3) was used as a negative control; mean velocity of organelle trafficking in cells expressing this protein was assigned 100% value in each experiment. In accord with a myosin-driven mechanism of MyoB compartment trafficking [30], GTD-K:HA3 expression significantly reduced the velocity of the endomembrane compartment tagged by MyoB1-GFP (Fig 1A; compare S1A and S1B Movie). Transient expression of the DUF593-1:HA3 or DUF593-2:HA3 also resulted in decreased velocities of MyoB1-GFP compartment trafficking, thus validating the dominant negative inhibition approach used in the following experiments (Fig 1A; S1C and S1D Movie). Given the similar expression levels of DUF593-1:HA3 and DUF593-2:HA3 (S1B Fig), the stronger inhibitory effect of the latter may be attributed to a relatively higher myosin-binding affinity of this domain.


Myosin-Powered Membrane Compartment Drives Cytoplasmic Streaming, Cell Expansion and Plant Development.

Peremyslov VV, Cole RA, Fowler JE, Dolja VV - PLoS ONE (2015)

Dominant negative inhibition of particulate trafficking in N. benthamiana leaf epidermal cells upon transient overexpression of β-glucuronidase (GUS; control), the globular tail domain of N. benthamiana myosin XI-K (XI-K GTD) and the myosin-binding DUF593 domains of N. benthamiana MyoB1 and MyoB2 (MyoB1 DUF593 and MyoB2 DUF593).The mean velocities (μm/sec) and standard deviations are shown for MyoB1 compartment tagged by full-size N. benthamiana MyoB1-GFP (A), Golgi stacks (B), mitochondria (C), peroxisomes (D), vesicles tagged by mCherry:VAMP721 (E) and inclusion bodies formed by the C-terminal fragment of mCherry-tagged, viral proteinμNS, mCherry-μNS (F). Percent of the mean velocity reduction relative to GUS control is shown below each column.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591342&req=5

pone.0139331.g001: Dominant negative inhibition of particulate trafficking in N. benthamiana leaf epidermal cells upon transient overexpression of β-glucuronidase (GUS; control), the globular tail domain of N. benthamiana myosin XI-K (XI-K GTD) and the myosin-binding DUF593 domains of N. benthamiana MyoB1 and MyoB2 (MyoB1 DUF593 and MyoB2 DUF593).The mean velocities (μm/sec) and standard deviations are shown for MyoB1 compartment tagged by full-size N. benthamiana MyoB1-GFP (A), Golgi stacks (B), mitochondria (C), peroxisomes (D), vesicles tagged by mCherry:VAMP721 (E) and inclusion bodies formed by the C-terminal fragment of mCherry-tagged, viral proteinμNS, mCherry-μNS (F). Percent of the mean velocity reduction relative to GUS control is shown below each column.
Mentions: The overexpression of the cargo binding, globular tail domain of N. benthamiana myosin XI-K (GTD-K:HA3) was used as a positive control in all dominant negative inhibition experiments because this domain has a strong inhibitory effect on myosin-dependent transport [22]. The bacterial β-glucuronidase (GUS:HA3) was used as a negative control; mean velocity of organelle trafficking in cells expressing this protein was assigned 100% value in each experiment. In accord with a myosin-driven mechanism of MyoB compartment trafficking [30], GTD-K:HA3 expression significantly reduced the velocity of the endomembrane compartment tagged by MyoB1-GFP (Fig 1A; compare S1A and S1B Movie). Transient expression of the DUF593-1:HA3 or DUF593-2:HA3 also resulted in decreased velocities of MyoB1-GFP compartment trafficking, thus validating the dominant negative inhibition approach used in the following experiments (Fig 1A; S1C and S1D Movie). Given the similar expression levels of DUF593-1:HA3 and DUF593-2:HA3 (S1B Fig), the stronger inhibitory effect of the latter may be attributed to a relatively higher myosin-binding affinity of this domain.

Bottom Line: Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics.Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming.It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, United States of America.

ABSTRACT
Using genetic approaches, particle image velocimetry and an inert tracer of cytoplasmic streaming, we have made a mechanistic connection between the motor proteins (myosins XI), cargo transported by these motors (distinct endomembrane compartment defined by membrane-anchored MyoB receptors) and the process of cytoplasmic streaming in plant cells. It is shown that the MyoB compartment in Nicotiana benthamiana is highly dynamic moving with the mean velocity of ~3 μm/sec. In contrast, Golgi, mitochondria, peroxisomes, carrier vesicles and a cytosol flow tracer share distinct velocity profile with mean velocities of 0.6-1.5 μm/sec. Dominant negative inhibition of the myosins XI or MyoB receptors using overexpression of the N. benthamiana myosin cargo-binding domain or MyoB myosin-binding domain, respectively, resulted in velocity reduction for not only the MyoB compartment, but also each of the tested organelles, vesicles and cytoplasmic streaming. Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics. Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming. It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering. These results support a model according to which myosin-dependent, MyoB receptor-mediated transport of a specialized membrane compartment that is conserved in all land plants drives cytoplasmic streaming that carries organelles and vesicles and facilitates cell growth and plant development.

No MeSH data available.


Related in: MedlinePlus