Calponin induces actin polymerization at low ionic strength and inhibits depolymerization of actin filaments

Kake, Takei; Kimura, Sumiko; Takahashi, Katsuhito; Maruyama, Kosçak

doi:10.1042/bj3120587

Cited by 47 publications

(40 citation statements)

References 33 publications

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“…The total F-actin was fractionated from the whole cell protein pool using well characterized procedures and detected using a b-actin antibody ( Fig. 3A) (Kake et al, 1995;Kim et al, 2008;Pan et al, 2011). Hence, in these studies, GAPDH was used as a loading control.…”

Section: Ndrg1 Inhibits F-actin Polymerization and Stressmentioning

confidence: 99%

Targeting the Metastasis Suppressor, NDRG1, Using Novel Iron Chelators: Regulation of Stress Fiber-Mediated Tumor Cell Migration via Modulation of the ROCK1/pMLC2 Signaling Pathway

et al. 2012

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The iron-regulated metastasis suppressor, N-myc downstreamregulated gene 1 (NDRG1), is up-regulated by cellular iron depletion mediated by iron chelators and can inhibit cancer cell migration. However, the mechanism of how NDRG1 achieves this effect remains unclear. In this study, we implemented established and newly constructed NDRG1 overexpression and knockdown models using the DU145, HT29, and HCT116 cancer cell lines to investigate the molecular basis by which NDRG1 exerts its inhibitory effect on cell migration. Using these models, we demonstrated that NDRG1 overexpression inhibits cell migration by preventing actin-filament polymerization, stress fiber assembly and formation. In contrast, NDRG1 knockdown had the opposite effect. Moreover, we identified that NDRG1 inhibited an important regulatory pathway mediated by the Rho-associated, coiled-coil containing protein kinase 1 (ROCK1)/phosphorylated myosin light chain 2 (pMLC2) pathway that modulates stress fiber assembly. The phosphorylation of MLC2 is a key process in inducing stress fiber contraction, and this was shown to be markedly decreased or increased by NDRG1 overexpression or knockdown, respectively. The mechanism involved in the inhibition of MLC2 phosphorylation by NDRG1 was mediated by a significant (P , 0.001) decrease in ROCK1 expression that is a key kinase involved in MLC2 phosphorylation. Considering that NDRG1 is up-regulated after cellular iron depletion, novel thiosemicarbazone iron chelators (e.g., di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone) were demonstrated to inhibit ROCK1/pMLC2-modulated actinfilament polymerization, stress fiber assembly, and formation via a mechanism involving NDRG1. These results highlight the role of the ROCK1/pMLC2 pathway in the NDRG1-mediated antimetastatic signaling network and the therapeutic potential of iron chelators at inhibiting metastasis.

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Section: Ndrg1 Inhibits F-actin Polymerization and Stressmentioning

confidence: 99%

Targeting the Metastasis Suppressor, NDRG1, Using Novel Iron Chelators: Regulation of Stress Fiber-Mediated Tumor Cell Migration via Modulation of the ROCK1/pMLC2 Signaling Pathway

et al. 2012

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“…It has been known that calponin interacts with F-actin, calmodulin, and tropomyosin, and functionally regulates the contraction and relaxation cycles in smooth muscle [14,15]. In addition, calponin induces actin polymerization and stabilizes formed actin filaments resulting in the maintenance of stress fibers [9]. Although calponin 1 and 2 are predominantly expressed in smooth muscle cells, calponin 3 is highly expressed in the central nervous system and its expression level is increased in neuropathologic conditions such as epilepsy.…”

Section: Discussionmentioning

confidence: 99%

Expression of Calponin 3 in the Striatum Following 3-Nitropropionic Acid-induced Neurotoxicity

Choi¹

2013

Journal of Life Science

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Calponin 3 is an F-actin-binding protein and plays a key role in regulating spine plasticity and synaptic activity in neurons. Unlike the other subtypes, calponin 1 and 2, which are expressed in smooth and cardiac muscle cells, calponin 3 is highly expressed in the brain. The goal of this study was to elucidate the spatiotemporal expression pattern of calponin 3 following repeated administration of 3-nitropropionic acid in mice. The repeated administration of 3-nitropropionic acid generated necrotic neuronal cell death in the striatum. Calponin 3 was up-regulated in the neuroprotective penimbral region from 1.5 days after the last injection and thereafter. Double immunofluorescence study revealed that calponin 3 was induced in GFAP-positive astrocytes. These results suggest that calponin 3 induction in the neuroprotective penumbral area following 3-nitropropionic acid intoxication may play a key role in reactive astrogliosis in the striatum.

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“…Calcium binding is also likely to play a role in regulating these actin modulators, and we provide preliminary evidence of GF-specific differences in calciumbinding capacity. Indeed, calcium is known to increase the association between calponins and caldesmon for regulation of smooth muscle cell contraction (41), with calponin also stimulating actin polymerization and bundling to stabilize actin microfilaments (47,48).…”

Section: Discussionmentioning

confidence: 99%

Functional Proteomic Analysis of Long-term Growth Factor Stimulation and Receptor Tyrosine Kinase Coactivation in Swiss 3T3 Fibroblasts

Nagano¹,

Akpan

Warnasuriya

et al. 2012

Molecular & Cellular Proteomics

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In Swiss 3T3 fibroblasts, long-term stimulation with PDGF, but not insulin-like growth factor 1 (IGF-1) or EGF, results in the establishment of an elongated migratory phenotype, characterized by the formation of retractile dendritic protrusions and absence of actin stress fibers and focal adhesion complexes. To identify receptor tyrosine kinasespecific reorganization of the Swiss 3T3 proteome during phenotypic differentiation, we compared changes in the pattern of protein synthesis and phosphorylation during long-term exposure to PDGF, IGF-1, EGF, and their combinations using 2DE-based proteomics after 35 S-and 33 P-metabolic labeling. One hundred and five differentially regulated proteins were identified by mass spectrometry and some of these extensively validated. PDGF stimulation produced the highest overall rate of protein synthesis at any given time and induced the most sustained phospho-signaling. Simultaneous activation with two or three of the growth factors revealed both synergistic and antagonistic effects on protein synthesis and expression levels with PDGF showing dominance over both IGF-1 and EGF in generating distinct proteome compositions. Using signaling pathway inhibitors, PI3K was identified as an early site for signal diversification, with sustained activity of the PI3K/AKT pathway critical for regulating late protein synthesis and phosphorylation of target proteins and required for maintaining the PDGF-dependent motile phenotype. Several proteins were identified with novel PI3K/ Akt-dependent synthesis and phosphorylations including eEF2, PRS7, RACK-1, acidic calponin, NAP1L1, Hsp73, and fascin. The data also reveal induction/suppression of key F-actin and actomyosin regulators and chaperonins that enable PDGFR to direct the assembly of a motile cytoskeleton, despite simultaneous antagonistic signaling activities. Together, the study demonstrates that longterm exposure to different growth factors results in receptor tyrosine kinase-specific regulation of relatively small subproteomes, and implies that the strength and longevity of receptor tyrosine kinase-specific signals are critical in defining the composition and functional activity of the resulting proteome. Molecular & Cellular Proteomics 11: 10.1074/mcp.M112.019778, 1690 -1708, 2012.Receptor tyrosine kinases transduce key extracellular signals and trigger multiple cellular events, including proliferation, differentiation, and cytoskeletal rearrangement. A variety of intracellular signaling molecules associate with the phosphorylated tyrosine residues on the cytoplasmic tail of activated receptor tyrosine kinase (RTKs) 1 via their Src homology 2 domain (SH2) or phosphotyrosine-binding (PTB) domains.

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Calponin induces actin polymerization at low ionic strength and inhibits depolymerization of actin filaments

Cited by 47 publications

References 33 publications

Targeting the Metastasis Suppressor, NDRG1, Using Novel Iron Chelators: Regulation of Stress Fiber-Mediated Tumor Cell Migration via Modulation of the ROCK1/pMLC2 Signaling Pathway

Targeting the Metastasis Suppressor, NDRG1, Using Novel Iron Chelators: Regulation of Stress Fiber-Mediated Tumor Cell Migration via Modulation of the ROCK1/pMLC2 Signaling Pathway

Expression of Calponin 3 in the Striatum Following 3-Nitropropionic Acid-induced Neurotoxicity

Functional Proteomic Analysis of Long-term Growth Factor Stimulation and Receptor Tyrosine Kinase Coactivation in Swiss 3T3 Fibroblasts

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