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Cybulsky AV, Guillemette J, Papillon J. Ste20-like kinase, SLK, activates the heat shock factor 1 - Hsp70 pathway. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1863:2147-55. [PMID: 27216364 DOI: 10.1016/j.bbamcr.2016.05.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/17/2016] [Accepted: 05/19/2016] [Indexed: 10/21/2022]
Abstract
Expression and activation of SLK increases during renal ischemia-reperfusion injury. When highly expressed, SLK signals via c-Jun N-terminal kinase and p38 to induce apoptosis, and it exacerbates apoptosis induced by ischemia-reperfusion injury. Overexpression of SLK in glomerular epithelial cells (GECs)/podocytes in vivo induces injury and proteinuria. In response to various stresses, cells enhance expression of chaperones or heat shock proteins (e.g. Hsp70), which are involved in the folding and maturation of newly synthesized proteins, and can refold denatured or misfolded proteins. We address the interaction of SLK with the heat shock factor 1 (HSF1)-Hsp70 pathway. Increased expression of SLK in GECs (following transfection) induced HSF1 transcriptional activity. Moreover, HSF1 transcriptional activity was increased by in vitro ischemia-reperfusion injury (chemical anoxia/recovery) and heat shock, and in both instances was amplified further by SLK overexpression. HSF1 binds to promoters of target genes, such as Hsp70 and induces their transcription. By analogy to HSF1, SLK stimulated Hsp70 expression. Hsp70 was also enhanced by anoxia/recovery and was further amplified by SLK overexpression. Induction of HSF1 and Hsp70 was dependent on the kinase activity of SLK, and was mediated via polo-like kinase-1. Transfection of constitutively active HSF1 enhanced Hsp70 expression and inhibited SLK-induced apoptosis. Conversely, the proapoptotic action of SLK was augmented by HSF1 shRNA, or the Hsp70 inhibitor, pifithrin-μ. In conclusion, increased expression/activity of SLK activates the HSF1-Hsp70 pathway. Hsp70 attenuates the primary proapoptotic effect of SLK. Modulation of chaperone expression may potentially be harnessed as cytoprotective therapy in renal cell injury.
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Affiliation(s)
- Andrey V Cybulsky
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada.
| | - Julie Guillemette
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Joan Papillon
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
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Fokin AI, Klementeva TS, Nadezhdina ES, Burakov AV. SLK/LOSK kinase regulates cell motility independently of microtubule organization and Golgi polarization. Cytoskeleton (Hoboken) 2016; 73:83-92. [PMID: 26818812 DOI: 10.1002/cm.21276] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 10/16/2015] [Accepted: 01/20/2016] [Indexed: 12/31/2022]
Abstract
Cell motility is an essential complex process that requires actin and microtubule cytoskeleton reorganization and polarization. Such extensive rearrangement is closely related to cell polarization as a whole. The serine/threonine kinase SLK/LOSK is a potential regulator of cell motility, as it phosphorylates a series of cytoskeleton-bound proteins that collectively participate in the remodeling of migratory cell architecture. In this work, we report that SLK/LOSK is an indispensable regulator of cell locomotion that primarily acts through the small GTPase RhoA and the dynactin subunit p150(Glued). Both RhoA and dynactin affect cytoskeleton organization, polarization, and general cell locomotory activity to various extents. However, it seems that these events are independent of each other. Thus, SLK/LOSK kinase effectively functions as a switch that links all of the processes underlying cell motility to provide robust directional movement.
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Affiliation(s)
- Artem I Fokin
- A.N.Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskye Gory, Moscow, 119992, Russia
| | - Tatiana S Klementeva
- Institute of Protein Research of Russian Academy of Sciences, Moscow Region, Pushchino, Institutskaya Str, 4, 142290, Russia
| | - Elena S Nadezhdina
- A.N.Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskye Gory, Moscow, 119992, Russia.,Institute of Protein Research of Russian Academy of Sciences, Moscow Region, Pushchino, Institutskaya Str, 4, 142290, Russia
| | - Anton V Burakov
- A.N.Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskye Gory, Moscow, 119992, Russia
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Zhapparova ON, Fokin AI, Vorobyeva NE, Bryantseva SA, Nadezhdina ES. Ste20-like protein kinase SLK (LOSK) regulates microtubule organization by targeting dynactin to the centrosome. Mol Biol Cell 2013; 24:3205-14. [PMID: 23985322 PMCID: PMC3806656 DOI: 10.1091/mbc.e13-03-0137] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The protein kinase SLK (LOSK) phosphorylates the 1A isoform of the p150Glued subunit of dynactin and targets it to the centrosome, where it maintains microtubule radial organization. In addition, dynactin phosphorylation is involved in Golgi reorientation in polarized cells. The microtubule- and centrosome-associated Ste20-like kinase (SLK; long Ste20-like kinase [LOSK]) regulates cytoskeleton organization and cell polarization and spreading. Its inhibition causes microtubule disorganization and release of centrosomal dynactin. The major function of dynactin is minus end–directed transport along microtubules in a complex with dynein motor. In addition, dynactin is required for maintenance of the microtubule radial array in interphase cells, and depletion of its centrosomal pool entails microtubule disorganization. Here we demonstrate that SLK (LOSK) phosphorylates the p150Glued subunit of dynactin and thus targets it to the centrosome, where it maintains microtubule radial organization. We show that phosphorylation is required only for centrosomal localization of p150Glued and does not affect its microtubule-organizing properties: artificial targeting of nonphosphorylatable p150Glued to the centrosome restores microtubule radial array in cells with inhibited SLK (LOSK). The phosphorylation site is located in a microtubule-binding region that is variable for two isoforms (1A and 1B) of p150Glued expressed in cultured fibroblast-like cells (isoform 1B lacks 20 amino acids in the basic microtubule-binding domain). The fact that SLK (LOSK) phosphorylates only a minor isoform 1A of p150Glued suggests that transport and microtubule-organizing functions of dynactin are distinctly divided between the two isoforms. We also show that dynactin phosphorylation is involved in Golgi reorientation in polarized cells.
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Affiliation(s)
- Olga N Zhapparova
- A. N. Belozersky Institute for Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia Institute of Protein Research, Russian Academy of Sciences, Moscow 117334, Russia
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Luhovy AY, Jaberi A, Papillon J, Guillemette J, Cybulsky AV. Regulation of the Ste20-like kinase, SLK: involvement of activation segment phosphorylation. J Biol Chem 2011; 287:5446-58. [PMID: 22203681 DOI: 10.1074/jbc.m111.302018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression and activation of the Ste20-like kinase, SLK, is increased during kidney development and recovery from ischemic acute kidney injury. SLK promotes apoptosis, and it may regulate cell survival during injury or repair. This study addresses the role of phosphorylation in the regulation of kinase activity. We mutated serine and threonine residues in the putative activation segment of the SLK catalytic domain and expressed wild type (WT) and mutant proteins in COS-1 or glomerular epithelial cells. Compared with SLK WT, the T183A, S189A, and T183A/S189A mutants showed reduced in vitro kinase activity. SLK WT, but not mutants, increased activation-specific phosphorylation of c-Jun N-terminal kinase (JNK) and p38 kinase. Similarly, SLK WT stimulated activator protein-1 reporter activity, but activation of activator protein-1 by the three SLK mutants was ineffective. To test if homodimerization of SLK affects phosphorylation, the cDNA encoding SLK amino acids 1-373 (which include the catalytic domain) was fused with a cDNA for a modified FK506-binding protein, Fv (Fv-SLK 1-373). After transfection, the addition of AP20187 (an FK506 analog) induced regulated dimerization of Fv-SLK 1-373. AP20187-stimulated dimerization enhanced the kinase activity of Fv-SLK 1-373 WT. In contrast, kinase activity of Fv-SLK 1-373 T183A/S189A was weak and was not enhanced after dimerization. Finally, apoptosis was increased after expression of Fv-SLK 1-373 WT but not T183A/S189A. Thus, phosphorylation of Thr-183 and Ser-189 plays a key role in the activation and signaling of SLK and could represent a target for novel therapeutic approaches to renal injury.
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Affiliation(s)
- Artem Y Luhovy
- Department of Medicine, McGill University Health Centre, McGill University, Montreal, Quebec H3A 1A1, Canada
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Burakov AV, Nadezhdina ES. Protein kinase LOSK regulates the network of microtubules and cell locomotion. Biophysics (Nagoya-shi) 2010. [DOI: 10.1134/s0006350910060059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Burakov AV, Zhapparova ON, Kovalenko OV, Zinovkina LA, Potekhina ES, Shanina NA, Weiss DG, Kuznetsov SA, Nadezhdina ES. Ste20-related protein kinase LOSK (SLK) controls microtubule radial array in interphase. Mol Biol Cell 2008; 19:1952-61. [PMID: 18287541 DOI: 10.1091/mbc.e06-12-1156] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Interphase microtubules are organized into a radial array with centrosome in the center. This organization is a subject of cellular regulation that can be driven by protein phosphorylation. Only few protein kinases that regulate microtubule array in interphase cells have been described. Ste20-like protein kinase LOSK (SLK) was identified as a microtubule and centrosome-associated protein. In this study we have shown that the inhibition of LOSK activity by dominant-negative mutant K63R-DeltaT or by LOSK depletion with RNAi leads to unfocused microtubule arrangement. Microtubule disorganization is prominent in Vero, CV-1, and CHO-K1 cells but less distinct in HeLa cells. The effect is a result neither of microtubule stabilization nor of centrosome disruption. In cells with suppressed LOSK activity centrosomes are unable to anchor or to cap microtubules, though they keep nucleating microtubules. These centrosomes are depleted of dynactin. Vero cells overexpressing K63R-DeltaT have normal dynactin "comets" at microtubule ends and unaltered morphology of Golgi complex but are unable to polarize it at the wound edge. We conclude that protein kinase LOSK is required for radial microtubule organization and for the proper localization of Golgi complex in various cell types.
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Affiliation(s)
- Anton V Burakov
- Institute of Protein Research, Russian Academy of Science, 142290 Pushchino, Moscow Region, Russian Federation
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Burakov AV, Kovalenko OV, Potekhina ES, Nadezhdina ES, Zinovkina LA. LOSK (SLK) protein kinase activity is necessary for microtubule organization in the interphase cell centrosome. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2006; 403:317-9. [PMID: 16358584 DOI: 10.1007/s10630-005-0123-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- A V Burakov
- Belozerskii Institute of Physicochemical Biology, Moscow State University, Vorob'evy gory, Moscow, 119899 Russia
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Ellinger-Ziegelbauer H, Karasuyama H, Yamada E, Tsujikawa K, Todokoro K, Nishida E. Ste20-like kinase (SLK), a regulatory kinase for polo-like kinase (Plk) during the G2/M transition in somatic cells. Genes Cells 2000; 5:491-8. [PMID: 10886374 DOI: 10.1046/j.1365-2443.2000.00337.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Activation of the cyclin-dependent kinase cdc2-cyclin B1 at the G2/M transition of the cell cycle requires dephosphorylation of threonine-14 and tyrosine-15 in cdc2, which in higher eukaryotes is brought about by the Cdc25C phosphatase. In Xenopus, there is evidence that a kinase cascade comprised of xPlkk1 and Plx1, the Xenopus polo-like kinase 1, plays a key role in the activation of Cdc25C during oocyte maturation. In the mammalian somatic cell cycle, a polo-like kinase homologue (Plk1) also functions during mitosis, but a kinase upstream of Plk is still unknown. RESULTS We show here that human Ste20-like kinase (SLK), which is a ubiquitously expressed mammalian protein related to xPlkk1, can phosphorylate and activate murine Plk1. During progression through the G2 phase of the mammalian cell cycle, the activity of endogenous SLK is increased. The amount of SLK protein is decreased in quiescent and differentiating cells. Treatment with okadaic acid induces a phosphorylation-dependent enhancement of SLK activity. CONCLUSIONS We propose that SLK has a role in the regulation of Plk1 activity in actively dividing cells during the somatic cell cycle. SLK itself is suggested to be regulated by phosphorylation.
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Affiliation(s)
- H Ellinger-Ziegelbauer
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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