scholarly journals Kindlin-2 promotes rear focal adhesion disassembly and directional persistence in cell migration

2020 ◽  
pp. jcs.244616
Author(s):  
Jie Liu ◽  
Zhongzhen Liu ◽  
Keng Chen ◽  
Wei Chen ◽  
Xiyuan Fang ◽  
...  
Keyword(s):  
Cell Migration ◽  
Focal Adhesion ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Molecular Level ◽  
Trailing Edge ◽  
Serum Stimulation ◽  
Actomyosin Contractility

Cell migration involves front-rear asymmetric FA dynamics, which facilitates trailing edge detachment and directional persistence. Here we show that kinldin-2 is critical for FA sliding and disassembly in migrating cells. Loss of kindlin-2 markedly reduced FA number and selectively impaired rear FA sliding and disassembly, resulting in defective rear retraction and reduced directional persistence during cell migration. Kindlin-2 deficient cells failed to develop serum-induced actomyosin-dependent tension at FAs. At the molecular level, kindlin-2 directly interacted with myosin light chain kinase (MLCK), which was enhanced in response to serum stimulation. Serum deprivation inhibited rear FA disassembly, which was released in response to serum stimulation. Overexpression of the MLCK-binding kindlin-2 F0F1 fragment (aa 1-167), which inhibits the interaction of endogenous kindlin-2 with MLCK, phenocopied kindlin-2 deficiency-induced migration defects. Inhibition of MLCK, like loss of kindlin-2, also impaired trailing edge detachment, rear FA disassembly and directional persistence. These results suggest a role of kindlin-2 in promoting actomyosin contractility at FAs, leading to increased rear FA sliding and disassembly and directional persistence in cell migration.

Role of myosin light chain kinase in cardiotrophin-1-induced cardiac myofibroblast cell migration

2011 ◽  
Vol 301 (2) ◽  
pp. H514-H522 ◽  
Author(s):  
Darren H. Freed ◽  
Lisa Chilton ◽  
Yun Li ◽  
Aran L. Dangerfield ◽  
Joshua E. Raizman ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Cell Migration ◽  
Membrane Potential ◽  
Light Chain ◽  
Intracellular Signaling ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Tissue Injury ◽  
Smooth Muscle Actin

Chemotactic movement of myofibroblasts is recognized as a common means for their sequestration to the site of tissue injury. Following myocardial infarction (MI), recruitment of cardiac myofibroblasts to the infarct scar is a critical step in wound healing. Contractile myofibroblasts express embryonic smooth muscle myosin, α-smooth muscle actin, as well as collagens I and III. We examined the effects of cardiotrophin-1 (CT-1) in the induction of primary rat ventricular myofibroblast motility. Changes in membrane potential (Em) and Ca2+entry were studied to reveal the mechanisms for induction of myofibroblast migration. CT-1-induced cardiac myofibroblast cell migration, which was attenuated through the inhibition of JAK2 (25 μM AG490), and myosin light chain kinase (20 μM ML-7). Inhibition of K+channels (1 mM tetraethylammonium or 100 μM 4-aminopyridine) and nonselective cation channels by 10 μM gadolinium (Gd3+) significantly reduced migration in the presence of CT-1. CT-1 treatment caused a significant increase in myosin light chain phosphorylation, which could be inhibited by incubation in Ca2+-free conditions or by application of AG490, ML-7, and W7 (100 μM; calmodulin inhibitor). Monitoring myofibroblast membrane potential with potentiometric fluorescent DiBAC4( 3 ) dye revealed a biphasic response to CT-1 consisting of an initial depolarization followed by hyperpolarization. Increased intracellular Ca2+, as assessed by fluo 3, occurred immediately after membrane depolarization and attenuated at the time of maximal hyperpolarization. CT-1 exerts chemotactic effects via multiple parallel signaling modalities in ventricular myofibroblasts, including changes in membrane potential, alterations in intracellular calcium, and activation of a number of intracellular signaling pathways. Further study is warranted to determine the precise role of K+currents in this process.

scholarly journals Role of myosin light chain kinase in regulation of basal blood pressure and maintenance of salt-induced hypertension

2011 ◽  
Vol 301 (2) ◽  
pp. H584-H591 ◽  
Author(s):  
Wei-Qi He ◽  
Yan-Ning Qiao ◽  
Cheng-Hai Zhang ◽  
Ya-Jing Peng ◽  
Chen Chen ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Vascular Tone ◽  
Induced Hypertension ◽  
Basal Blood Pressure ◽  
Muscle Myosin

Vascular tone, an important determinant of systemic vascular resistance and thus blood pressure, is affected by vascular smooth muscle (VSM) contraction. Key signaling pathways for VSM contraction converge on phosphorylation of the regulatory light chain (RLC) of smooth muscle myosin. This phosphorylation is mediated by Ca2+/calmodulin-dependent myosin light chain kinase (MLCK) but Ca2+-independent kinases may also contribute, particularly in sustained contractions. Signaling through MLCK has been indirectly implicated in maintenance of basal blood pressure, whereas signaling through RhoA has been implicated in salt-induced hypertension. In this report, we analyzed mice with smooth muscle-specific knockout of MLCK. Mesenteric artery segments isolated from smooth muscle-specific MLCK knockout mice (MLCKSMKO) had a significantly reduced contractile response to KCl and vasoconstrictors. The kinase knockout also markedly reduced RLC phosphorylation and developed force. We suggest that MLCK and its phosphorylation of RLC are required for tonic VSM contraction. MLCKSMKO mice exhibit significantly lower basal blood pressure and weaker responses to vasopressors. The elevated blood pressure in salt-induced hypertension is reduced below normotensive levels after MLCK attenuation. These results suggest that MLCK is necessary for both physiological and pathological blood pressure. MLCKSMKO mice may be a useful model of vascular failure and hypotension.

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