Outer Dense Fibers Serve as a Functional Target for Cdk5·p35 in the Developing Sperm Tail

Rosales, Jesusa L.; Lee, Byung‐Chul; Modarressi, Mohammad Hossein; Sarker, Krishna Pada; Lee, Kyoung-Youl; Jeong, Young‐Gil; Oko, Richard; Lee, Ki-Young

doi:10.1074/jbc.m310867200

Cited by 37 publications

(37 citation statements)

References 52 publications

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“…23 Recently, several studies have shown that CDK5 plays an important role in the exocytosis, differentiation, and senescence of nonneuronal cells such as pancreatic ␤ cells, 24,25 monocytes, 26 muscle cells, 27 and testis. 28 For example, CDK5 regulates glucose-induced insulin exocytosis by phosphorylating Munc18 25 or the L-type voltage-dependent calcium channel 24 in pancreatic ␤ cells. In muscle cells, CDK5 phosphorylates nestin, the intermediate filament protein, which plays an important role in muscle development and regeneration.…”

Section: Figurementioning

confidence: 99%

Cyclin-Dependent Kinase 5 Phosphorylates Endothelial Nitric Oxide Synthase at Serine 116

Cho

Seo²,

Park³

et al. 2010

Hypertension

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Abstract-Nitric oxide (NO) production in endothelial cells (EC) is regulated by multisite phosphorylation of specific serine and threonine residues in endothelial NO synthase (eNOS). Among these, eNOS-Ser116 is phosphorylated in the basal state, and its phosphorylation contributes to basal NO production. Here, we investigated the mechanism by which eNOS-Ser116 is phosphorylated during the basal state using bovine aortic EC. Although a previous study suggested that protein kinase C was involved in eNOS-Ser116 phosphorylation, overexpression of various protein kinase C isoforms did not affect eNOS-Ser116 phosphorylation. An in silico analysis using a motif scan revealed that the eNOS-Ser116 residue might be a substrate for proline-directed protein kinases. Roscovitine, a specific inhibitor of cyclin-dependent kinase (CDK), 1, 2, and 5, but not an inhibitor of mitogen-activated protein kinase kinase or glycogen synthase kinase 3␤, inhibited eNOS-Ser116 phosphorylation dose dependently. Furthermore, purified CDK1, 2, or 5 directly phosphorylated eNOS-Ser116 in vitro. Ectopic expression of the dominant-negative CDK5 but not dominant-negative CDK1 or dominant-negative CDK2 repressed eNOS-Ser116 phosphorylation and increased NO production. In addition, CDK5 activity was detected in bovine aortic EC, and coimmunoprecipitation and confocal microscopy studies revealed a colocalization of eNOS and CDK5. Cotransfection of CDK5 and p25, the specific CDK5 activator, increased eNOS-Ser116 phosphorylation and decreased NO production, but its parent molecule, p35, and p39, another activator, were not detected in bovine aortic EC, which suggests the existence of a novel CDK5 activator. Overall, this is the first study to find that CDK5 is a physiological kinase responsible for eNOS-Ser116 phosphorylation and regulation of NO production. Key Words: nitric oxide Ⅲ endothelial nitric oxide synthase Ⅲ cyclin-dependent kinase 5 Ⅲ endothelium Ⅲ phosphorylation Ⅲ signal transduction E ndothelial nitric oxide synthase (eNOS) is an essential enzyme responsible for the production of endotheliumderived nitric oxide (NO), which is a key molecule with multiple functions, including vascular homeostasis, angiogenesis, and cell cycle regulation. 1,2 The dysregulation of eNOS, therefore, contributes to the pathogenesis of certain diseases, such as atherosclerosis, hypertension, and cancer. 2 It is well known that eNOS is regulated at the level of its phosphorylation. 3,4 Several specific sites of phosphorylation have been identified, among which eNOS-Ser1179 (bovine sequence) and eNOS-Thr497 have been the most thoroughly evaluated. The phosphorylation of eNOS-Ser1179 increases NO production, 5-7 which is mediated by several specific protein kinases, including Akt, AMP-activated protein kinase, calmodulin-dependent kinase II, and protein kinase A (PKA). 8 -11 Conversely, the phosphorylation of eNOS-Thr497 decreases eNOS activity, 8,10 which is mediated by AMP-activated protein kinase 5 and protein kinase C (PKC). 10,12 This site is also dephosph...

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Section: Figurementioning

confidence: 99%

Cyclin-Dependent Kinase 5 Phosphorylates Endothelial Nitric Oxide Synthase at Serine 116

Cho

Seo²,

Park³

et al. 2010

Hypertension

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“…Cdk5 is most abundant in neurons and its activators, p35 and p39, have been presumed to be neuronspecific. Although Cdk5 activity has generally been associated with brain, recent studies have implicated a role for Cdk5 in other tissues such as muscle (11,12), ocular lens (13), and testis (14). It seems that Cdk5 modulates cell differentiation and certain cellular functions.…”

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confidence: 99%

GTP-dependent Secretion from Neutrophils Is Regulated by Cdk5

Rosales

Ernst

Hallows

et al. 2004

Journal of Biological Chemistry

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We have previously shown evidence for the existence of a calcium-independent, GTP-regulated mechanism of secretion from neutrophils, but this secretory mechanism remains to be fully elucidated. Cyclin-dependent kinase 5 (Cdk5), the various substrates of which include Munc18 and synapsin 1, has been implicated in neuronal secretion. Although the Cdk5 activator, p35, and Cdk5-p35 activity are primarily associated with neurons, we report here that p35 also exists in neutrophils and that an active Cdk5-p35 complex is present in these cells. Cdk5-p35 activity in human neutrophils is mostly localized in secretory granules, which show an increase in Cdk5-p35 level and activity upon GTP stimulation. The potent Cdk5 inhibitor, roscovitine, completely blocks GTP-stimulated granule Cdk5 activity, which accompanies lactoferrin secretion from neutrophil-specific granules. Roscovitine also inhibits GTP-induced lactoferrin secretion and surface localization of the secretion markers, CD63 and CD66b, to a certain extent. Furthermore, neutrophils from wild-type mice treated with roscovitine and neutrophils from p35 ؊/؊ mice exhibit comparable surface expression levels of both CD63 and CD66b upon GTP stimulation. Although our data suggest that other molecules control GTP-induced secretion from neutrophils, it is clear that Cdk5-p35 is required to elicit the maximum GTP-induced secretory response. Our observation that multiple proteins in neutrophil granules serve as specific substrates of Cdk5 further supports the premise that the kinase is a key component of the GTPregulated secretory apparatus in neutrophils.

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“…Cdk5 requires its regulatory partner, p35 (or its potent truncated form, p25) (Lew and Wang, 1995;Lee et al, 1997) or its isoform, p39 (Tang et al, 1995) for activity. Although Cdk5 activity has mostly been associated with brain, more recent studies indicate that Cdk5 plays an important role in other tissues as well such as muscle (Sahlgren et al, 2003), ocular lens (Gao et al, 2002) and testis (Rosales et al, 2004b (Inada et al, 1999;Cheng et al, 2000;Lee et al, 2005). Indeed, vimentin is phosphorylated by protein kinase A, protein kinase C, and CaMKII at specific serine sites (Izawa and Inagaki, 2006) and this has been associated with disassembly of the vimentin intermediate filaments (Eriksson et al, 1992).…”

Section: Cihr Author Manuscriptmentioning

confidence: 99%

“…Cdk5 requires its regulatory partner, p35 (or its potent truncated form, p25) (Lew and Wang, 1995;Lee et al, 1997) or its isoform, p39 (Tang et al, 1995) for activity. Although Cdk5 activity has mostly been associated with brain, more recent studies indicate that Cdk5 plays an important role in other tissues as well such as muscle (Sahlgren et al, 2003), ocular lens (Gao et al, 2002) and testis (Rosales et al, 2004b). It appears that Cdk5 regulates cell differentiation and certain specialized cell functions (Rosales and Lee, 2006), including wound healing (Gao et al, 2004), gene transcription (Fu et al, 2004), senescence (Alexander et al, 2004), and secretion (Rosales et al, 2004a).…”

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confidence: 99%

Cdk5 mediates vimentin ser56 phosphorylation during GTP‐induced secretion by neutrophils

Lee

Liu

Jin

et al. 2011

Journal Cellular Physiology

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Secretion by neutrophils contributes to acute inflammation following injury or infection. Vimentin has been shown to be important for secretion by neutrophils but little is known about its dynamics during secretion, which is regulated by cyclin-dependent kinase 5 (Cdk5). In this study, we sought to examine the vimentin dynamics and its potential regulation by Cdk5 during neutrophil secretion. We show that vimentin is a Cdk5 substrate that is specifically phosphorylated at Ser56. In response to neutrophil stimulation with GTP, vimentin Ser56 was phosphorylated and colocalized with Cdk5 in the cytoplasmic compartment. Vimentin pSer56 and Cdk5 colocalization was consistent with coimmunoprecipitation from stimulated cells. Vimentin Ser56 phosphorylation occurred immediately after stimulation, and a remarkable increase in phosphorylation was noted later in the secretory process. Decreased GTP-induced vimentin Ser56 phosphorylation and secretion resulted from inhibition of Cdk5 activity by roscovitine or olomoucine or by depletion of Cdk5 by siRNA, suggesting that GTP-induced Cdk5-mediated vimentinSer56 phosphorylation may be related to GTP-inducedCdk5-mediated secretion by neutrophils. Indeed, inhibition of vimentin Ser56 phosphorylation led to a corresponding inhibition of GTP-induced secretion, indicating a link between these two events. While fMLP also induced vimentin Ser56 phosphorylation, such phosphorylation was unaffected by roscovitine, which nonetheless, inhibited secretion, suggesting that Cdk5 regulates fMLP-induced secretion via a mechanism independent of Cdk5-mediated vimentin Ser56 phosphorylation. These findings demonstrate the distinct involvement of Cdk5 in GTP-and fMLP-induced secretion by neutrophils, and support the notion that specific targeting of Cdk5 may serve to inhibit the neutrophil secretory process.The neutrophil is the first cell type recruited to a site of infection or inflammation. One of the mechanisms used by the neutrophil to destroy infectious agents or to mediate the inflammatory process in a variety of clinical scenarios is to secrete its granule contents. Regulation of secretion from the neutrophil is key to the balance between host defense and tissue injury (Nathan, 2006 CIHR Author ManuscriptCIHR Author Manuscript CIHR Author Manuscript independent GTP-regulated mechanism of secretion in neutrophils (Rosales and Ernst, 2000). Other nucleotide-mediated mechanisms of activation in neutrophils such as adenosine-5′-triphosphate (ATP)-and uridine-5′-triphosphate (UTP)-induced stimulation have been shown to be regulated by protein kinases, including the p38 mitogen-activated protein kinase (p38MAPK) and the extracellular signal-regulated kinase (ERK1/2) (Meshki et al., 2004). Our studies showed that GTP-dependent secretion from neutrophils is mediated by cyclin-dependent kinase 5 (Cdk5) (Rosales et al., 2004a). However, the mechanisms underlying this process remain to be investigated.Cdk5, a small proline-directed serine/threonine kinase, has close structural homology with...

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Outer Dense Fibers Serve as a Functional Target for Cdk5·p35 in the Developing Sperm Tail

Cited by 37 publications

References 52 publications

Cyclin-Dependent Kinase 5 Phosphorylates Endothelial Nitric Oxide Synthase at Serine 116

Cyclin-Dependent Kinase 5 Phosphorylates Endothelial Nitric Oxide Synthase at Serine 116

GTP-dependent Secretion from Neutrophils Is Regulated by Cdk5

Cdk5 mediates vimentin ser56 phosphorylation during GTP‐induced secretion by neutrophils

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