Polo-like Kinase 1 Regulates Vimentin Phosphorylation at Ser-56 and Contraction in Smooth Muscle

Abstract

Polo-like kinase 1 (Plk1) is a serine/threonine-protein kinase that has been implicated in mitosis, cytokinesis, and smooth muscle cell proliferation. The role of Plk1 in smooth muscle contraction has not been investigated. Here, stimulation with acetylcholine induced Plk1 phosphorylation at Thr-210 (an indication of Plk1 activation) in smooth muscle. Contractile stimulation also activated Plk1 in live smooth muscle cells as evidenced by changes in fluorescence resonance energy transfer signal of a Plk1 sensor. Moreover, knockdown of Plk1 in smooth muscle attenuated force development. Smooth muscle conditional knock-out of Plk1 also diminished contraction of mouse tracheal rings. Plk1 knockdown inhibited acetylcholine-induced vimentin phosphorylation at Ser-56 without affecting myosin light chain phosphorylation. Expression of T210A Plk1 inhibited the agonist-induced vimentin phosphorylation at Ser-56 and contraction in smooth muscle. However, myosin light chain phosphorylation was not affected by T210A Plk1. Ste20-like kinase (SLK) is a serine/threonine-protein kinase that has been implicated in spindle orientation and microtubule organization during mitosis. In this study knockdown of SLK inhibited Plk1 phosphorylation at Thr-210 and activation. Finally, asthma is characterized by airway hyperresponsiveness, which largely stems from airway smooth muscle hyperreactivity. Here, smooth muscle conditional knock-out of Plk1 attenuated airway resistance and airway smooth muscle hyperreactivity in a murine model of asthma. Taken together, these findings suggest that Plk1 regulates smooth muscle contraction by modulating vimentin phosphorylation at Ser-56. Plk1 activation is regulated by SLK during contractile activation. Plk1 contributes to the pathogenesis of asthma.

The roles and regulation of the actin cytoskeleton, intermediate filaments and microtubules in smooth muscle cell migration

“…External stimulation induces vimentin phosphorylation at Ser-56, which leads to reorganization of the vimentin network, facilitating mechanical force transduction in smooth muscle. Vimentin phosphorylation at Ser-56 is catalyzed by p21-activated kinase 1 (PAK1) and polo-like kinase 1 (Plk1) in smooth muscle [50, 52, 67, 68]. Vimentin dephosphorylation at this residue is regulated protein phosphatase 1 in smooth muscle [49] (Fig.…”

“…First, vimentin phosphorylation at Ser-56 by PAK1 and Plk1 leads to its disassembly in smooth muscle, which results in the release of CAS from cytoskeletal vimentin. CAS translocates to the cell cortex and promotes the Arp2/3 complex-mediated actin polymerization and branching, and lamellipodial formation [2, 34, 35, 50, 52, 65, 67, 74] (Fig. 4b).…”

Non‐canonical cM et regulation by vimentin mediates Plk1 inhibitor–induced apoptosis

“…Plk1 further phosphorylates vimentin at S82 (Oguri et al , ; Yamaguchi et al , ), which regulates vimentin filament segregation, coordinately with rho‐kinase and Aurora‐B (Yamaguchi et al , ). Recently, another study also demonstrated that Plk1 regulates smooth muscle contraction by modulating vimentin phosphorylation at S56 (Li et al , ). In addition, Plk1 regulates cell surface levels of β1‐integrin and invasion by phosphorylating vimentin in breast cancer cells (Rizki et al , ).…”

Role and regulation of Abelson tyrosine kinase in Crk-associated substrate/profilin-1 interaction and airway smooth muscle contraction

“…Human airway smooth muscle (HASM) cells were previously described by our laboratory [ 11 – 14 , 28 ]. This study was approved by the Albany Medical College Committee on Research Involving Human Subjects.…”

“…A pool of globular actin (G-actin) is added to existing filamentous actin (F-actin) in response to contractile stimulation, which promotes contraction by enhancing the transmission of force between the contractile units and the extracellular matrix [ 4 , 6 – 10 ]. Thus, myosin can be viewed as an “engine” and the actin cytoskeleton as a “transmission system” for smooth muscle contraction [ 4 , 11 – 14 ]. Although myosin activation has been extensively investigated [ 1 , 2 ], the cellular processes that orchestrate actin polymerization are incompletely elucidated.…”