Phosphorylation of cortactin by p21-activated kinase

Webb, Bradley A.; Zhou, Shutang; Eves, Robert; Shen, Linda; Jia, Lilly; Mak, Alan S.

doi:10.1016/j.abb.2006.06.011

Cited by 78 publications

(96 citation statements)

References 57 publications

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“…Interestingly, the serine/threonine kinase PAK1 was identified to directly phosphorylate cortactin on serine 113 thereby down-regulating F-actin binding to cortactin (34). We here describe a similar mechanism for PKD-mediated phosphorylation of cortactin on Ser 298 .…”

Section: Discussionmentioning

confidence: 61%

Protein Kinase D Controls Actin Polymerization and Cell Motility through Phosphorylation of Cortactin

Eiseler

Haußer

Kimpe

et al. 2010

Journal of Biological Chemistry

121

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We here identify protein kinase D (PKD) as an upstream regulator of the F-actin-binding protein cortactin and the Arp actin polymerization machinery. PKD phosphorylates cortactin in vitro and in vivo at serine 298 thereby generating a 14-3-3 binding motif. In vitro, a phosphorylation-deficient cortactin-S298A protein accelerated VCA-Arp-cortactin-mediated synergistic actin polymerization and showed reduced F-actin binding, indicative of enhanced turnover of nucleation complexes. In vivo, cortactin co-localized with the nucleation promoting factor WAVE2, essential for lamellipodia extension, in the actin polymerization zone in Heregulin-treated MCF-7 cells. Using a 3-dye FRET-based approach we further demonstrate that WAVE2-Arp and cortactin prominently interact at these structures. Accordingly, cortactin-S298A significantly enhanced lamellipodia extension and directed cell migration. Our data thus unravel a previously unrecognized mechanism by which PKD controls cancer cell motility.The mechanistic elucidation of signaling pathways regulating dynamic actin remodeling processes in migrating cells is pivotal to a comprehensive understanding of cancer cell metastasis. Protein kinase D (PKD) 2 has recently been identified as a vital upstream regulator of polarized cell motility and F-actin organization (1-4). PKD localizes to sites of dynamic actin remodeling (1). The kinase activity is essential for the control of directed cell motility (1, 2), whereby active PKD1 inhibited, whereas kinase-inactive PKD1KD strongly enhanced motility and invasiveness (1-4). Mechanistically, a key role for PKD1 in controlling the activity of the ubiquitous F-actin depolymerizing-and severing factor cofilin via slingshot1L (SSH1L) cofilin phosphatase has been demonstrated. The activity of SSH1L is mainly regulated by its binding to filamentous actin (F-actin), which has been shown to strongly enhance its activity (5, 6). Phosphorylation of SSH1L at Ser 978 by active PKD1, e.g. downstream of RhoA or oxidative stress, generates a 14-3-3 binding motif within an important F-actin binding region, thus resulting in the sequestration of SSH1L away from dynamic actin structures, reducing SSH1 activity and active non-S3-phosphorylated cofilin levels (2). By severing actin filaments, cofilin increases both the availability of G-actin monomers as well as the number of "barbed ends" for polymerization (7). Furthermore, severed filaments are the preferred substrate for dendritic nucleation by the Arp complex (8, 9). Localized induction of actin polymerization and the formation of branched actin networks constitute the basis for membrane protrusion and cell motility (2, 10, 11). In line with an upstream regulatory role in the control of these processes, PKD1 and -2 are also capable of binding to F-actin in vitro (1). In the case of PKD1, in vivo F-actin binding has been demonstrated as well, which most likely facilitates an interaction with actin regulatory proteins such as SSH1L (2). We now have identified a second key regulatory signaling pathway ...

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Section: Discussionmentioning

confidence: 61%

Protein Kinase D Controls Actin Polymerization and Cell Motility through Phosphorylation of Cortactin

Eiseler

Haußer

Kimpe

et al. 2010

Journal of Biological Chemistry

121

View full text Add to dashboard Cite

show abstract

“…Pak1 might regulate actin dynamics by phosphorylating cortactin (Webb et al, 2006), an actin-binding protein present at developing NMJs (Peng et al, 1997). Pak1 also suppresses myosin light chain kinase (MLCK) and thus reduces the phosphorylation of myosin light chains (MLCs) and the association of MLCs with actin filaments.…”

Section: Agrin/lrp4/musk Signalingmentioning

confidence: 99%

To build a synapse: signaling pathways in neuromuscular junction assembly

2010

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SummarySynapses, as fundamental units of the neural circuitry, enable complex behaviors. The neuromuscular junction (NMJ) is a synapse type that forms between motoneurons and skeletal muscle fibers and that exhibits a high degree of subcellular specialization. Aided by genetic techniques and suitable animal models, studies in the past decade have brought significant progress in identifying NMJ components and assembly mechanisms. This review highlights recent advances in the study of NMJ development, focusing on signaling pathways that are activated by diffusible cues, which shed light on synaptogenesis in the brain and contribute to a better understanding of muscular dystrophy. Key words: Neural development, Neuromuscular junction, Retrograde signaling, Synapse formation IntroductionThe brain contains billions of nerve cells, or neurons, which receive and integrate signals from the environment, and which govern the body's responses. Nervous system activity is made possible by synapses, contacts formed either between neurons or between a neuron and a target cell. Synapses are asymmetric structures in which neurotransmitter molecules are released from the presynaptic membrane and activate receptors on the postsynaptic membrane, thus establishing neuronal communication. As such, synapses are fundamental units of neural circuitry and enable complex behaviors. The neuromuscular junction (NMJ) is a type of synapse formed between motoneurons and skeletal muscle fibers. Large and easily accessed experimentally, this peripheral synapse has contributed greatly to the understanding of the general principles of synaptogenesis and to the development of potential therapeutic strategies for muscular disorders. The NMJ uses different neurotransmitters in different species; for example, acetylcholine (ACh) in vertebrates and glutamate in Drosophila, both of which are excitatory and cause muscle contraction. In Caenorhabditis elegans, there are two types of NMJs: at excitatory NMJs, ACh causes muscle contraction, whereas inhibitory NMJs release g-aminobutyric acid (GABA) to cause muscle relaxation. Motor nerve terminals differentiate to form presynaptic active zones, where synaptic vesicles dock and release neurotransmitters. On the apposed postsynaptic membranes, neurotransmitter receptors are packed at high densities. Aided by genetic techniques and by the use of suitable animal models, including rodents, zebrafish, Drosophila and C. elegans, studies in the past decade have brought significant progress, not only in identifying components present in pre-and postsynaptic membranes, but also in understanding the mechanisms that underpin NMJ assembly. This review highlights recent advances in the study of NMJ development, focusing on signaling pathways that are activated by diffusible cues from motor nerves and muscle fibers. Readers are referred to other outstanding reviews for a broad view of NMJ development (see Froehner, 1993;Hall and Sanes, 1993;Kummer et al., 2006;Salpeter and Loring, 1985;Schaeffer et al., 2001). NMJ formati...

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“…Indeed, addition of myosin inhibitors rescued matrix degradation in Quint actopaxin U2OS cells as well as cell invasion of Quint actopaxin MDA-MB-231 cells. Conversely, both the Cdc42/Rac1 GEF, ␤-PIX, and its effector and binding partner PAK1 have previously been reported to be required for invadopodia formation and function, but little is known about the mechanism regulating their activity in this context (28,(43)(44)(45). Actopaxin binding to ␤-PIX provides a new mechanism by which ␤-PIX and PAK1 may be recruited to adhesions to coordinate their turnover during migration and/or transformation to invasive structures.…”

Section: Discussionmentioning

confidence: 99%