Mechanism of regulation of actin polymerization by Physarum profilin.

Ozaki, Katsuya; Hatano, Sadashi

doi:10.1083/jcb.98.6.1919

Cited by 36 publications

(19 citation statements)

References 35 publications

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“…Fission yeast profilin Cdc3 inhibited nucleation of fission yeast and muscle actins and decreased the extent of polymerization of both actins in a concentration-dependent manner, as previously described for Physarum profilin (70). Moreover, we showed for the first time that profilin significantly shortened the average length of actin filaments at steady state.…”

Section: Discussionsupporting

confidence: 59%

Properties of Actin from the Fission Yeast Schizosaccharomyces pombe and Interaction with Fission Yeast Profilin

Takaine

Mabuchi

2007

Journal of Biological Chemistry

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The fission yeast Schizosaccharomyces pombe serves as a model system for studying role of actin cytoskeleton, since it has simple actin cytoskeletons and is genetically tractable. In contrast, biochemical approaches using this organism are still developing; fission yeast actin has so far not been isolated in its native form and characterized, and therefore, biochemical assays of fission yeast actin-binding proteins (ABPs) or myosin have been performed using rabbit skeletal muscle actin that may interact with the fission yeast ABPs in a manner different from fission yeast actin. Here, we report a novel method for isolating functionally active actin from fission yeast cells. The highly purified fission yeast actin polymerized with kinetics somewhat different from those of muscle actin and forms filaments that are structurally indistinguishable from skeletal muscle actin filaments. The fission yeast actin was a significantly weaker activator of Mg 2؉ -ATPase of HMM of skeletal muscle myosin than muscle actin. The fission yeast profilin Cdc3 suppressed polymerization of fission yeast actin more effectively than that of muscle actin and showed an affinity for fission yeast actin higher than for muscle actin. The establishment of purification of fission yeast actin will enable reconstruction of physiologically relevant interactions between the actin and fission yeast ABPs or myosins and contribute to clarification of function of actin cytoskeleton in various cellular activities.The actin cytoskeleton is involved in many cellular motile processes, such as muscle contraction, migration of the cell, cytoplasmic streaming, organelle positioning, cell morphogenesis, and cytokinesis. In many cases, the actin cytoskeleton is dynamic and is constructed and destroyed during the cell cycle or in response to extracellular stimuli. The dynamic nature is important for functions of the actin cytoskeleton; many actin cytoskeletons are formed only when they are necessary for specific cellular activities to be exercised. For example, the contractile ring forms in the equatorial cortex of the cell only during cytokinesis, constricts the cell into two, and is no longer present when cytokinesis is completed. The dynamic nature is mainly attributed to a couple of factors. One is the intrinsic feature of actin itself (i.e. it polymerizes into filaments and depolymerizes responding to environmental conditions). The others are regulation of the assembly feature of actin by actinmodulating proteins and formation of three-dimensional structures of actin filaments by various actin-cross-linking proteins, activities of both of which may be further controlled by upstream signaling pathways. Therefore, analyses of both assembly properties of actin and actions of various actin-binding proteins are requisite for understanding the dynamic nature of each actin cytoskeleton.The fission yeast Schizosaccharomyces pombe serves as a good model system for studying the actin cytoskeletal organization, since the cells have only three distinct F-actin structur...

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Section: Discussionsupporting

confidence: 59%

Properties of Actin from the Fission Yeast Schizosaccharomyces pombe and Interaction with Fission Yeast Profilin

Takaine

Mabuchi

2007

Journal of Biological Chemistry

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“…The double mutation E361A, D363N had increased affinity for profilin. Although the D363N change exists in a Dictyostelium actin, its effects cannot be dismissed as insignificant as different actin isoforms can have different affinities for profilin (Ozaki et al, 1983;Ohshima et al, 1989). It is therefore unclear if either one or both of the changes are important for the effect on profilin binding.…”

Section: Amino Acid At Position 363mentioning

confidence: 99%

The binding of mutant actins to profilin, ATP and DNase I

Drummond

Hennessey

Sparrow

1992

European Journal of Biochemistry

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Twenty-five mutations were created in the Drosophilu melunogcister Act88F actin gene by in vitro mutagenesis and the mutant actins expressed in vitro. The affinity of the mutant actins for ATP, profilin and DNase I was determined. They were also tested for conformational changes by nondenaturing gel electrophoresis. Mutations at positions 364 (highly conserved) and 366 (invariant) caused changes in conformation, reduced ATP binding and increased profilin binding. At position 362 (invariant) only the conservative change from tyrosine to phenylalanine had no effect; other changes at this position affected conformation, ATP and profilin binding. Although only glycine or serine occur naturslly at position 368, changes to threonine or glutamine had no effect on the actin. The mutant in which Asp363 was replaced by His and that in which Glu364 was replaced by Lys decreased DNase I binding, yet neither amino acid occurs in the DNase I binding site. Likewise several mutations affect ATP and profilin binding but are distant from the bindng sites.We conclude that, although actin has a highly conserved amino acid sequence, individual amino acids can have variable tolerance for substitutions. Also amino acid changes can exert significant effects on the binding of ligands to distant parts of the actin structure.

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“…Its given name referred to this property, as it kept actin in the form of "pro-filamentous actin." Since then, we learned that profilins constitute a large family of proteins, generated mainly by separate genes, but in some cases also as splice products, in lower eukaryotes (Cooley et al 1992;Haugwitz et al 1991;Ozaki et al 1983;Reichstein and Korn 1979;Tilney et al 1983;Wilkes and Otto 2000;Wilkes and Otto 2003), plants (Staiger et al 1993;Valenta et al 1993), invertebrates (Cooley et al 1992;Polet et al 2006;Somboonwiwat et al 2006) and vertebrates (Braun et al 2002;Honoré et al 1993;Witke et al 1998Witke et al , 2001. There is even a viral profilin (Blasco et al 1991) whose gene organization is homologous to the mammalian profilins and may thus have been highjacked from a mammalian host cell.…”

Section: Introductionmentioning

confidence: 99%

The profile of profilins

Jockusch

Murk

Rothkegel

2007

Reviews of Physiology, Biochemistry and Pharmacology

123

105

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Profilins are small proteins involved in actin dynamics. In accordance with this function, they are found in all eukaryotes and are structurally highly conserved. However, their precise role in regulating actin-related functions is just beginning to emerge. This article recapitulates the wealth of information on structure, expression and functions accumulated on profilins from many different organisms in the 30 years after their discovery as actin-binding proteins. Emphasis is given to their interaction with a plethora of many different ligands in the cytoplasm as well as in the nucleus, which is considered the basis for their various activities and the significance of the tissue-specific expression of profilin isoforms.

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Mechanism of regulation of actin polymerization by Physarum profilin.

Cited by 36 publications

References 35 publications

Properties of Actin from the Fission Yeast Schizosaccharomyces pombe and Interaction with Fission Yeast Profilin

Properties of Actin from the Fission Yeast Schizosaccharomyces pombe and Interaction with Fission Yeast Profilin

The binding of mutant actins to profilin, ATP and DNase I

The profile of profilins

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