Vinexin Forms a Signaling Complex with Sos and Modulates Epidermal Growth Factor-induced c-Jun N-terminal Kinase/Stress-activated Protein Kinase Activities

Akamatsu, Masahiko; Aota, Shin-ichi; Suwa, Akira; Ueda, Kazumitsu; Amachi, Teruo; Yamada, Katsushi; Akiyama, Steven K.; Kioka, Noriyuki

doi:10.1074/jbc.274.50.35933

Cited by 44 publications

(64 citation statements)

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“…However, it is possible that the ␤-catenin⅐lp-dlg⅐vinexin complex can link cadherin to actin cytoskeleton through vinexin binding to vinculin and contribute to the formation of cell-cell contacts. Alternatively, ␤-catenin⅐lp-dlg complex might compete with the vinexin binding to Sos, a guanine nucleotide exchange factor for Ras and Rac, and modulate the signaling, because both Sos and lp-dlg bind to the third SH3 domain of vinexin ␤ (14). Further studies are necessary to examine these possibilities.…”

Section: Discussionmentioning

confidence: 99%

“…To define the lp-dlg binding site of vinexin ␤, a deletion mutant containing only the third SH3 domain was excised from plasmids of GST-3rdSH3 (14) and subcloned into pGBT9. Deletion mutants containing the second and third SH3 (amino acids 120 -328) and the linker (amino acids 173-271) region of mouse vinexin ␤ were amplified by polymerase chain reaction and subcloned into pGBT9.…”

Section: Methodsmentioning

confidence: 99%

“…In Vitro Binding Assay Using Affinity Precipitation-The GST-fused proteins containing vinexin deletion mutants, GST-1stSH3, GST2ndSH3, GST-3rdSH3, GST-3rdSH3WF, and GST-3rdSH3YV were described previously (14). Full-length vinexin ␤ was subcloned into pGEX4T-1.…”

Section: Methodsmentioning

confidence: 99%

“…Vinexin binds to vinculin, which also localizes at cell-cell and cell-matrix junctions, through its first and second SH3 domains and enhances actin stress fiber formation and cell spreading (9). Furthermore, vinexin ␤ regulates the anchorage dependence of extracellular signal-regulated kinase activation induced by epidermal growth factor (13,14). Therefore, vinexin plays a crucial role in regulating cellextracellular matrix communication, but little is known about the function of vinexin at cell-cell junctions.…”

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Interaction of lp-dlg/KIAA0583, a Membrane-associated Guanylate Kinase Family Protein, with Vinexin and β-Catenin at Sites of Cell-Cell Contact

Wakabayashi

Ito

Mitsushima

et al. 2003

Journal of Biological Chemistry

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Vinexin is a recently identified cytoskeletal protein and plays a key role in the regulation of cytoskeletal organization and signal transduction. Vinexin localizes at sites of cell-extracellular matrix adhesion in NIH3T3 fibroblasts and at sites of cell-cell contact in epithelial LLC-PK1 cells. Expression of vinexin promotes the formation of actin stress fiber, but the role of vinexin at sites of cell-cell contact is unclear. Here we identified lp-dlg/KIAA0583 as a novel binding partner for vinexin by using yeast two-hybrid screening. lp-dlg/KIAA0583 has a NH 2 -terminal coiled-coil-like domain, in addition to four PDZ domains, an Src homology (SH) 3 domain, and a guanylate kinase domain, which are conserved structures in membrane-associated guanylate kinase family proteins. The third SH3 domain of vinexin bound to the region between the second and third PDZ domain of lp-dlg, which contains a proline-rich sequence. lp-dlg colocalized with vinexin at sites of cell-cell contact in LLC-PK1 cells. Furthermore, lp-dlg colocalized with ␤-catenin, a major adherens junction protein, in LLC-PK1 cells. Co-immunoprecipitation experiments revealed that both endogenous and epitope-tagged deletion mutants of lp-dlg/KIAA0583 associated with ␤-catenin. We also showed that these three proteins could form a ternary complex. Together these findings suggest that lp-dlg/KIAA0583 is a novel scaffolding protein that can link the vinexin-vinculin complex and ␤-catenin at sites of cell-cell contact.Cell-cell adhesion is important for cell polarity, tissue morphogenesis development, and homeostasis (1-3). To this end, epithelial cells exhibit specialized structures involved in cell-cell contacts such as tight junctions and adherens junctions. Adherens junctions contain the transmembrane cell adhesion molecules, cadherins and nectins, which mediate the calcium-dependent and -independent cell-cell adhesion (1, 3, 4), respectively. The cytoplasmic domain of cadherin binds to ␤-catenin, which then binds to ␣-catenin. ␣-Catenin binds to actin and actin-binding proteins such as vinculin, ␣-actinin, and ZO-1, resulting in the link of cadherin to the actin cytoskeleton (3, 5, 6). The cytoplasmic domain of nectin binds to l-afadin, which then binds to actin and a vinculin-binding protein ponsin (4,7,8). Multiple protein complexes of these cytoplasmic proteins play important roles in communicating between cell adhesion systems, regulating cellcell adhesion, and transducing signals into cells.Vinexin is a protein localizing at cell-cell and cell-extracellular matrix junctions (9). There are at least two types of vinexin, vinexin ␣ and vinexin ␤, which share a common carboxyl-terminal sequence containing three SH (Src homology) 3 1 domains. The larger vinexin ␣ has an additional amino-terminal sequence containing a sorbin homology domain. Vinexin is a member of a novel adaptor protein family, including ArgBP2 and ponsin, all of which have a sorbin homology domain in the NH 2 -terminal half and three SH3 domains in the COOHterminal half (8 -12). Vin...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Interaction of lp-dlg/KIAA0583, a Membrane-associated Guanylate Kinase Family Protein, with Vinexin and β-Catenin at Sites of Cell-Cell Contact

Wakabayashi

Ito

Mitsushima

et al. 2003

Journal of Biological Chemistry

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“…We previously showed that expression of vinexin ␣ affected the actin cytoskeletal organization in NIH3T3 cells, and that expression of vinexin ␤ promoted the spreading of C2C12 cells (18). Moreover, vinexin ␤ regulates the EGF-induced activation of JNK and the anchoragedependent activation of ERK2 induced by EGF (20,21). Furthermore, it was reported that vinexin interacted with scaffold attachment factor B2 or estrogen receptor, both of which are implicated in the response to steroid hormone (22,23).…”

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confidence: 99%

Extracellular Signal-regulated Kinase Activated by Epidermal Growth Factor and Cell Adhesion Interacts with and Phosphorylates Vinexin

Mitsushima

Suwa

Amachi

et al. 2004

Journal of Biological Chemistry

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Extracellular signal-regulated kinase 1/2 (ERK1/2) is activated by various extracellular stimuli including growth factors and cytokines and plays a pivotal role in regulating cell proliferation and differentiation by phosphorylating nuclear transcription factors. Recently, it was reported that activated ERK1/2 also concentrates at adhesion sites and regulates cell spreading and migration. Vinexin is a focal adhesion protein regulating both cell spreading and growth factor signaling. We show here that vinexin was directly phosphorylated by ERK1/2 upon stimulation with growth factors. ERK1/2 phosphorylated the linker region of vinexin between the second and third SH3 domains. Site-directed mutagenesis revealed that ERK2 mainly phosphorylated the serine 189 residue of vinexin ␤. Furthermore, vinexin ␤ interacted with ERK1/2 both in vitro and in vivo. Vinexin interacted with the active but not inactive form of ERK1/2. A putative DEF (docking for ERK FXFP) domain located in the linker region of vinexin was required for the interaction with ERK1/2 and efficient phosphorylation of vinexin ␤ by ERK2. Finally, we showed that cell adhesion to fibronectin also induced the association of vinexin ␤ with ERK2 and the phosphorylation of vinexin ␤. Furthermore, vinexin and ERK were co-localized to the periphery of cells during cell spreading on fibronectin. Together, these results suggest that vinexin is a novel substrate of ERK2 and may play roles in ERK-dependent cell regulation during cell spreading as well as in growth factor-induced responses.Mitogen-activated protein kinase (MAPK) 1 consists of four subfamilies, extracellular signal-regulated kinase 1/2 (ERK1/ 2), c-Jun N-terminal kinase/stress-activated kinase, p38MAPK, and ERK5. ERK1/2 is mainly activated by various growth factors and regulates a diverse array of cellular events including cell proliferation, survival, and differentiation (1, 2). Many extracellular signals activate membrane receptors, including receptor tyrosine kinases, G protein-coupled receptors, or integrins, leading to the activation of Raf. Activated Raf, in turn, activates MEK (MAPK/ERK kinase) by the direct phosphorylation of dual serine residues. Activated MEK also directly phosphorylates and activates ERK1/2. Once activated, ERK1/2 enters the nucleus and phosphorylates nuclear transcription factors, including Elk-1, Sap1, c-Myc, and c-Fos (3).Recently, ERK has been shown to play crucial roles in regulating cell adhesion and cell migration independent of its nuclear functions (4 -7). ERK is involved in the migration of breast cancer cells stimulated by urokinase-type tissue plasminogen activator. Neither de novo gene transcription nor protein synthesis is required for this process (5). Activation of ERK is also suggested to be involved in the chemotaxis or the extension of pseudopodia, probably through the phosphorylation of cytoplasmic proteins (8, 9). Furthermore, ERK is well known to be activated by integrin engagement and to be localized to adhesion sites (7, 10 -14). Although some cytoplasm...

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MiR‐484 promotes nonalcoholic fatty liver disease progression in mice via downregulation of Sorbs2

Jia,

Pan,

Liu

et al. 2023

Obesity

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ObjectiveMicroRNA 484 (miR‐484) plays a pivotal role in the development and progression of different diseases and is typically described as a mitochondrial regulator. Whether miR‐484 is involved in lipid metabolism or exerts a role in nonalcoholic fatty liver disease remains unclear.MethodsmiR‐484 levels were examined in the livers of male mice fed a high‐fat diet and in hepatocytes treated with free fatty acids. Sorbin and SH3 structural domain‐containing protein 2 (Sorbs2) were identified as a novel target of miR‐484 by sequencing mRNA in the livers of miR‐484 knockout mice. Sorbs2 liver‐specific knockdown mice were constructed by tail vein injection of adeno‐associated virus vector to miR‐484 knockout mice. In addition, genetic manipulation of SORBS2 was performed in human hepatocyte lines, mouse primary hepatocytes, and the liver.ResultsSerum and hepatic miR‐484 levels are upregulated in nonalcoholic fatty liver disease mice. miR‐484 knockdown ameliorated hepatocyte steatosis, whereas miR‐484 overexpression increased hepatocyte lipid load. miR‐484 knockdown‐mediated alleviation of hepatic steatosis, liver injury, inflammation, and apoptosis was compromised after high‐fat diet‐induced knockdown of Sorbs2 in mouse liver and free fatty acid‐induced primary mouse hepatocytes.ConclusionsThese results identify Sorbs2‐mediated mitochondrial β‐oxidation and apoptosis that promote miR‐484 knockdown‐mediated remission of hepatic steatosis.image

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Vinexin Forms a Signaling Complex with Sos and Modulates Epidermal Growth Factor-induced c-Jun N-terminal Kinase/Stress-activated Protein Kinase Activities

Cited by 44 publications

References 48 publications

Interaction of lp-dlg/KIAA0583, a Membrane-associated Guanylate Kinase Family Protein, with Vinexin and β-Catenin at Sites of Cell-Cell Contact

Interaction of lp-dlg/KIAA0583, a Membrane-associated Guanylate Kinase Family Protein, with Vinexin and β-Catenin at Sites of Cell-Cell Contact

Extracellular Signal-regulated Kinase Activated by Epidermal Growth Factor and Cell Adhesion Interacts with and Phosphorylates Vinexin

MiR‐484 promotes nonalcoholic fatty liver disease progression in mice via downregulation of Sorbs2

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