Faculty Opinions recommendation of Par-3 mediates the inhibition of LIM kinase 2 to regulate cofilin phosphorylation and tight junction assembly.

2006 ◽  
Author(s):  
Keith Mostov
Keyword(s):  
Tight Junction ◽  
Lim Kinase ◽  
Cofilin Phosphorylation

scholarly journals Par-3 mediates the inhibition of LIM kinase 2 to regulate cofilin phosphorylation and tight junction assembly

2006 ◽  
Vol 172 (5) ◽  
pp. 671-678 ◽  
Author(s):  
Xinyu Chen ◽  
Ian G. Macara
Keyword(s):  
Tight Junction ◽  
Cell Polarization ◽  
Actin Dynamics ◽  
Lim Kinase ◽  
Kinase C ◽  
Cofilin Phosphorylation ◽  
Upstream Kinase ◽  
Novel Target ◽  
Axon Specification

The polarity protein Par-3 plays critical roles in axon specification and the establishment of epithelial apico-basal polarity. Par-3 associates with Par-6 and atypical protein kinase C and is required for the proper assembly of tight junctions, but the molecular basis for its functions is poorly understood. We now report that depletion of Par-3 elevates the phosphorylated pool of cofilin, a key regulator of actin dynamics. Expression of a nonphosphorylatable mutant of cofilin partially rescues tight junction assembly in cells lacking Par-3, as does the depletion of LIM kinase 2 (LIMK2), an upstream kinase for cofilin. Par-3 binds to LIMK2 but not to the related kinase LIMK1. Par-3 inhibits LIMK2 activity in vitro, and overexpressed Par-3 suppresses cofilin phosphorylation that is induced by lysophosphatidic acid. Our findings identify LIMK2 as a novel target of Par-3 and uncover a molecular mechanism by which Par-3 could regulate actin dynamics during cell polarization.

scholarly journals A quantitative proteomic analysis of cofilin phosphorylation in myeloid cells and its modulation using the LIM kinase inhibitor Pyr1

PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0208979 ◽  
Author(s):  
Renaud Prudent ◽  
Nathalie Demoncheaux ◽  
Hélène Diemer ◽  
Véronique Collin-Faure ◽  
Reuben Kapur ◽  
...  
Keyword(s):  
Proteomic Analysis ◽  
Kinase Inhibitor ◽  
Myeloid Cells ◽  
Lim Kinase ◽  
Quantitative Proteomic Analysis ◽  
Cofilin Phosphorylation

scholarly journals Hyperosmotic stress induces Rho/Rho kinase/LIM kinase-mediated cofilin phosphorylation in tubular cells: key role in the osmotically triggered F-actin response

2009 ◽  
Vol 296 (3) ◽  
pp. C463-C475 ◽  
Author(s):  
Ana C. P. Thirone ◽  
Pam Speight ◽  
Matthew Zulys ◽  
Ori D. Rotstein ◽  
Katalin Szászi ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
De Novo ◽  
Rho Kinase ◽  
Small Gtpases ◽  
Hyperosmotic Stress ◽  
Dominant Negative ◽  
Lim Kinase ◽  
Tubular Cells ◽  
Cofilin Phosphorylation ◽  
Underlying Mechanisms

Hyperosmotic stress induces cytoskeleton reorganization and a net increase in cellular F-actin, but the underlying mechanisms are incompletely understood. Whereas de novo F-actin polymerization likely contributes to the actin response, the role of F-actin severing is unknown. To address this problem, we investigated whether hyperosmolarity regulates cofilin, a key actin-severing protein, the activity of which is inhibited by phosphorylation. Since the small GTPases Rho and Rac are sensitive to cell volume changes and can regulate cofilin phosphorylation, we also asked whether they might link osmostress to cofilin. Here we show that hyperosmolarity induced rapid, sustained, and reversible phosphorylation of cofilin in kidney tubular (LLC-PK1 and Madin-Darby canine kidney) cells. Hyperosmolarity-provoked cofilin phosphorylation was mediated by the Rho/Rho kinase (ROCK)/LIM kinase (LIMK) but not the Rac/PAK/LIMK pathway, because 1) dominant negative (DN) Rho and DN-ROCK but not DN-Rac and DN-PAK inhibited cofilin phosphorylation; 2) constitutively active (CA) Rho and CA-ROCK but not CA-Rac and CA-PAK induced cofilin phosphorylation; 3) hyperosmolarity induced LIMK-2 phosphorylation, and 4) inhibition of ROCK by Y-27632 suppressed the hypertonicity-triggered LIMK-2 and cofilin phosphorylation.We thenexamined whether cofilin and its phosphorylation play a role in the hypertonicity-triggered F-actin changes. Downregulation of cofilin by small interfering RNA increased the resting F-actin level and eliminated any further rise upon hypertonic treatment. Inhibition of cofilin phosphorylation by Y-27632 prevented the hyperosmolarity-provoked F-actin increase. Taken together, cofilin is necessary for maintaining the osmotic responsiveness of the cytoskeleton in tubular cells, and the Rho/ROCK/LIMK-mediated cofilin phosphorylation is a key mechanism in the hyperosmotic stress-induced F-actin increase.

Parkin interacts with LIM Kinase 1 and reduces its cofilin-phosphorylation activity via ubiquitination

2007 ◽  
Vol 313 (13) ◽  
pp. 2858-2874 ◽  
Author(s):  
Meng K. Lim ◽  
Takeshi Kawamura ◽  
Yosuke Ohsawa ◽  
Masafumi Ohtsubo ◽  
Shuichi Asakawa ◽  
...  
Keyword(s):  
Lim Kinase ◽  
Lim Kinase 1 ◽  
Cofilin Phosphorylation

scholarly journals Regulation of LIM-kinase 1 and cofilin in thrombin-stimulated platelets

Blood ◽  
2006 ◽  
Vol 107 (2) ◽  
pp. 575-583 ◽  
Author(s):  
Dharmendra Pandey ◽  
Pankaj Goyal ◽  
James R. Bamburg ◽  
Wolfgang Siess
Keyword(s):  
Shape Change ◽  
Rho Kinase ◽  
Lim Kinase ◽  
Kinase Activation ◽  
Integrin Αiibβ3 ◽  
Lim Kinase 1 ◽  
Filament Dynamics ◽  
Cofilin Phosphorylation ◽  
High Concentrations ◽  
Platelet Shape

Abstract Cofilin is a regulator of actin filament dynamics. We studied whether during platelet activation Rho kinase stimulates LIM kinase (LIMK) leading to subsequent phosphorylation and inactivation of cofilin. Platelet shape change and aggregation/secretion were induced by low and high concentrations of thrombin, respectively. We found that during these platelet responses Rho kinase activation was responsible for mediating rapid Thr508 phosphorylation and activation of LIMK-1 and for the F-actin increase during shape change and, in part, during secretion. Surprisingly, during shape change cofilin phosphorylation was unaltered, and during aggregation/secretion cofilin was first rapidly dephosphorylated by an okadaic acid–insensitive phosphatase and then slowly rephosphorylated by LIMK-1. LIMK-1 phosphorylation and cofilin dephosphorylation and rephosphorylation during aggregation were independent of integrin αIIbβ3 engagement. Cofilin phosphorylation did not regulate cofilin association with F-actin and was unrelated to the F-actin increase in thrombin-activated platelets. Our study identifies LIMK-1 as being activated by Rho kinase in thrombin-stimulated platelets. Two counteracting pathways, a cofilin phosphatase and LIMK-1, are activated during platelet aggregation/secretion regulating cofilin phosphorylation sequentially and independently of integrin αIIbβ3 engagement. Rho kinase–mediated F-actin increase during platelet shape change and secretion involves a mechanism other than LIMK-1–mediated cofilin phosphorylation, raising the possibility of another LIMK substrate regulating platelet actin assembly.

Regulation of ADF/cofilin phosphorylation and synaptic function by LIM-kinase

2004 ◽  
Vol 47 (5) ◽  
pp. 746-754 ◽  
Author(s):  
Yanghong Meng ◽  
Hisaaki Takahashi ◽  
Jinsong Meng ◽  
Yu Zhang ◽  
Guijin Lu ◽  
...  
Keyword(s):  
Synaptic Function ◽  
Lim Kinase ◽  
Cofilin Phosphorylation

scholarly journals Nischarin Inhibits LIM Kinase To Regulate Cofilin Phosphorylation and Cell Invasion

2008 ◽  
Vol 28 (11) ◽  
pp. 3742-3756 ◽  
Author(s):  
Yuemin Ding ◽  
Tanja Milosavljevic ◽  
Suresh K. Alahari
Keyword(s):  
Breast Cancer ◽  
Cell Invasion ◽  
Breast Cancer Cells ◽  
Lim Kinase ◽  
Random Migration ◽  
Downstream Effector ◽  
Cofilin Phosphorylation ◽  
P21 Activated Kinase ◽  
Interfering Rna ◽  
Novel Protein

ABSTRACT Nischarin is a novel protein that regulates cell migration by inhibiting p21-activated kinase (PAK). LIM kinase (LIMK) is a downstream effector of PAK, and it is known to play an important role in cell invasion. Here we show that nischarin also associates with LIMK to inhibit LIMK activation, cofilin phosphorylation, and LIMK-mediated invasion of breast cancer cells, suggesting that nischarin regulates cell invasion by negative modulation of the LIMK/cofilin pathway. The amino terminus of nischarin binds to the PDZ and kinase domains of LIMK. Although LIMK activation enhances the interaction with nischarin, only phosphorylation of threonine 508 of LIMK is crucial for the interaction. Inhibition of endogenous nischarin expression by RNA interference stimulates breast cancer cell invasion. Also, nischarin small interfering RNA (siRNA) enhances cofilin phosphorylation. In addition, knock-down of nischarin showed branched projection actin structures. Collectively these data indicate that nischarin siRNA may enhance random migration, resulting in stimulation of invasion.

Abstract 466: Redox Regulation of 14-3-3zeta Controls Monocyte Migration

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Hong Seok Kim ◽  
Sarah Ullevig ◽  
Jahyun Joo ◽  
Reto Asmis
Keyword(s):  
Metabolic Disorders ◽  
Redox Regulation ◽  
Protein S ◽  
Fold Increase ◽  
Vascular Lesions ◽  
Blood Monocytes ◽  
Lim Kinase ◽  
Monocyte Migration ◽  
Cofilin Phosphorylation ◽  
Actin Turnover

Cofilin regulates actin turnover and is inactivated by phosphorylation at Ser-3 by LIM kinase (LIMK) and reactivated by the cofilin-phosphatase Slingshot-1L (SSH1L). We recently reported that protein-S-glutathionylation induced by metabolic disorders enhances monocyte recruitment into vascular lesions. Because monocyte priming and accelerated migration involves increases actin turnover, we tested the hypothesis that these regulators of actin assembly/disassembly are redox-regulated. Metabolic priming was induced in human THP-1 monocytes by exposing the cells to diabetic conditions, i.e. human native LDL plus high glucose concentrations (LDL+HG). Phosphorylation of cofilin in response to MCP-1 was completely blocked in metabolically primed monocytes, suggesting that hyperactivation of cofilin may contribute to the enhanced chemotactic activity of primed monocytes. Yet, neither LIMK1 nor SSH1L levels were affected by metabolic stress. However, metabolic priming resulted in a 3.8-fold increase the S-glutathionylation of 14-3-3zeta, a SSH1L binding protein which maintains the cofilin phosphatase in an inactive state. S-glutathionylation of 14-3-3zeta resulted in its caspase-dependent degradation and a 35% reduction in 14-3-3zeta protein levels. Overexpression of glutaredoxin 1 in monocytes inhibited both LDL+HG-induced S-glutathionylation and degradation of 14-3-3zeta, and normalized cofilin phosphorylation in response to MCP-1. The C25S mutant of 14-3-3zeta was resistant to S-glutathionylation and degradation induced by LDL+HG, and restored MCP-1-induced cofilin phosphorylation in metabolically primed monocytes. 14-3-3zeta S-glutathionylation did not affect binding of 14-3-3zeta to SSH1L, suggesting that loss of 14-3-3zeta increases the pool of free SSH1L phosphatase, thus preventing the phosphorylation and deactivation of cofilin in response to chemokine activation. In conclusion, we identified a novel redox-sensitive mechanism for the regulation of monocyte migration that links (thiol) oxidative stress induced by metabolic disorders to monocyte dysfunction and the conversion of blood monocytes into a hypermigratory, proinflammatory and proatherogenic phenotype.

Role of LIM Kinase in Oncogenic Signaling from FLT3 and KIT Receptors and Its Targeting in Myeloid Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1257-1257 ◽  
Author(s):  
Ruchi Pandey ◽  
Raghuveer Mali ◽  
Anindya Chatterjee ◽  
Fabrice Paublant ◽  
Renaud Prudent ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Poor Prognosis ◽  
Leukemic Cells ◽  
Apoptosis Induction ◽  
Oncogenic Signaling ◽  
Leukemic Transformation ◽  
Lim Kinase ◽  
Cofilin Phosphorylation ◽  
Induction Of Apoptosis

Abstract Acute Myeloid leukemia (AML) has a poor prognosis in part due to lack of elimination of leukemic cells and acquisition of drug resistance. In particular mutations in the activation loop of KIT and internal tandem duplication (ITD) in Flt3 receptor are associated with poor prognosis in AML. Interestingly, more than 90% patients with aggressive systemic mastocytosis (ASM) carry the KITD816V mutation which is highly resistant to conventional therapeutics and invariably associated with poor survival. Since the efforts to target the kinase activity of FLT3 and KIT have met with little success; the focus has shifted to targeting critical downstream signaling regulators. We have elucidated the role of a novel downstream regulator of FLT3-ITD and KITD816V mediated leukemic transformation - LIM kinase and evaluated the efficacy of a novel inhibitor of LIM kinase (LIMK), Liminib. LIMK, a serine/threonine kinase has 2 isoforms; LIMK1 and LIMK2. They are substrates of the Rho associated kinase (ROCK) which we have shown to play a critical role in leukemic transformation (Cancer Cell, 2011). They in turn act on cofilin and phosphorylation by LIMK inactivates cofilin and thereby modulates F-actin reorganization. Western blot analysis showed marked increase in phospho cofilin levels in cells expressing FLT3-ITD or KITD814V oncogenes as compared to their WT counterparts. Dependence of cofilin phosphorylation on activation of ROCK and LIMK was confirmed by treating the cells with an inhibitor of ROCK, H1152 and Liminib, inhibitor of LIMK. Both the inhibitors effectively reduced oncogene-induced phospho-cofilin levels. Liminib, the LIMK inhibitor also inhibited cytokine independent proliferation driven by FLT3-ITD or KITD814V (>90% at 100 nM). It also showed concentration dependent inhibition of proliferation in mutant oncogene bearing patient derived human cell lines such as MV411, Kasumi and HMC. FLT3-ITD expressing leukemic cells become resistant to Flt3 kinase inhibitor AC220 by acquiring additional point mutations. Interestingly, the cells expressing AC220 resistant FLT3-ITDD835F or FLT3-ITDF691L mutation showed similar sensitivity to Liminib as cells with FLT3-ITD. The growth inhibitory effect of Liminib was also validated in primary blasts from AML and SM patients. To further elucidate the mechanism of growth inhibition by Liminib in leukemic cells, we assayed for apoptosis induction in the treated cells. Cells expressing FLT3-ITD were significantly more susceptible (~ 73%) to induction of apoptosis as compared the WT-FLT3 cells (~33%) on treatment with Liminib. The extent of apoptosis induction by Liminib was similar in FLT3-ITD and AC220 resistant FLT3-ITDD835F or FLT3-ITDF691L mutation bearing cells. In addition to the effects of Liminib on F-actin polymerization; experimental evidence indicates involvement of mitochondrial pathway in the induction of apoptosis by Liminib. There was increase in accumulation of cofilin in the mitochondrial fraction in Liminib treated oncogene expressing cells as compared to the untreated cells. Phosphorylation of cofilin on Ser3 suppresses its mitochondrial translocation and treatment with LIMK inhibitor would inhibit cofilin phosphorylation leading to increased mitochondrial transport. Mitochondrial transport of cofilin has been observed with other inducers of apoptosis such as staurosporine and it possibly contributes to mitochondrial dysfunction during induction of apoptosis. To validate our pharmacologic findings using Liminib genetically and to assess which of the 2 isoforms of LIMK contributes to leukemogenesis, we generated LIMK1 and LIMK2 single and double knockout mice. 3 H-thymidine incorporation assay showed that deletion of either of the LIMK significantly reduced KIT D814V induced growth factor independent proliferation by approximately 50%. The extent of inhibition was more pronounced in Limk1-/- Limk2+/- or Limk1+/- Limk2-/- bone marrow cells (~80%) as compared to cells with deletion of a single isoforms of LIMK. Thus, there is some functional redundancy between the 2 isoforms and inhibition of both is likely to have better therapeutic value. Taken together we have identified a novel signaling pathway involving LIMK and cofilin that appear to be selectively activated in regulating oncogenic signaling in AML and MPN but not in normal hematopoiesis. Disclosures No relevant conflicts of interest to declare.

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