文献一覧: Kojiro Mukai (著者)

4 0 0 0 OA FilGAP, a GAP for Rac1, down-regulates invadopodia formation in breast cancer cells

著者: Koji Saito Sakino Ozawa Yosuke Chiba Ruri Takahashi Ryoya Ogomori Kojiro Mukai Tomohiko Taguchi Hiroyasu Hatakeyama Yasutaka Ohta
出版者: Japan Society for Cell Biology
雑誌: Cell Structure and Function (ISSN:03867196)
巻号頁・発行日: pp.23032, (Released:2023-07-22)

Invadopodia are protrusive structures that mediate the extracellular matrix (ECM) degradation required for tumor invasion and metastasis. Rho small GTPases regulate invadopodia formation, but the molecular mechanisms of how Rho small GTPase activities are regulated at the invadopodia remain unclear. Here we have identified FilGAP, a GTPase-activating protein (GAP) for Rac1, as a negative regulator of invadopodia formation in tumor cells. Depletion of FilGAP in breast cancer cells increased ECM degradation and conversely, overexpression of FilGAP decreased it. FilGAP depletion promoted the formation of invadopodia with ECM degradation. In addition, FilGAP depletion and Rac1 overexpression increased the emergence of invadopodia induced by epidermal growth factor, whereas FilGAP overexpression suppressed it. Overexpression of GAP-deficient FilGAP mutant enhanced invadopodia emergence as well as FilGAP depletion. The pleckstrin-homology (PH) domain of FilGAP binds phosphatidylinositol 3,4-bisphosphate [PI(3,4)P2], which is distributed on membranes of the invadopodia. FilGAP localized to invadopodia in breast cancer cells on the ECM, but FilGAP mutant lacking PI(3,4)P2-binding showed low localization. Similarly, the decrease of PI(3,4)P2 production reduced the FilGAP localization. Our results suggest that FilGAP localizes to invadopodia through its PH domain binding to PI(3,4)P2 and down-regulates invadopodia formation by inactivating Rac1, inhibiting ECM degradation in invasive tumor cells.Key Words: Invadopodia, breast carcinoma, Rac1, FilGAP, PI(3,4)P2

2023-10-26 01:28:09
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3 0 0 0 OA FilGAP, a GAP for Rac1, down-regulates invadopodia formation in breast cancer cells

著者: Koji Saito Sakino Ozawa Yosuke Chiba Ruri Takahashi Ryoya Ogomori Kojiro Mukai Tomohiko Taguchi Hiroyasu Hatakeyama Yasutaka Ohta
出版者: Japan Society for Cell Biology
雑誌: Cell Structure and Function (ISSN:03867196)
巻号頁・発行日: vol.48, no.2, pp.161-174, 2023 (Released:2023-09-23)
参考文献数: 47

Invadopodia are protrusive structures that mediate the extracellular matrix (ECM) degradation required for tumor invasion and metastasis. Rho small GTPases regulate invadopodia formation, but the molecular mechanisms of how Rho small GTPase activities are regulated at the invadopodia remain unclear. Here we have identified FilGAP, a GTPase-activating protein (GAP) for Rac1, as a negative regulator of invadopodia formation in tumor cells. Depletion of FilGAP in breast cancer cells increased ECM degradation and conversely, overexpression of FilGAP decreased it. FilGAP depletion promoted the formation of invadopodia with ECM degradation. In addition, FilGAP depletion and Rac1 overexpression increased the emergence of invadopodia induced by epidermal growth factor, whereas FilGAP overexpression suppressed it. Overexpression of GAP-deficient FilGAP mutant enhanced invadopodia emergence as well as FilGAP depletion. The pleckstrin-homology (PH) domain of FilGAP binds phosphatidylinositol 3,4-bisphosphate [PI(3,4)P2], which is distributed on membranes of the invadopodia. FilGAP localized to invadopodia in breast cancer cells on the ECM, but FilGAP mutant lacking PI(3,4)P2-binding showed low localization. Similarly, the decrease of PI(3,4)P2 production reduced the FilGAP localization. Our results suggest that FilGAP localizes to invadopodia through its PH domain binding to PI(3,4)P2 and down-regulates invadopodia formation by inactivating Rac1, inhibiting ECM degradation in invasive tumor cells.Key words: invadopodia, breast carcinoma, Rac1, FilGAP, PI(3,4)P2

2023-09-27 12:53:13
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2 0 0 0 OA A non-nucleotide agonist that binds covalently to cysteine residues of STING

著者: Kentaro Matsumoto Shenwei Ni Hiroyuki Arai Takashi Toyama Yoshiro Saito Takehiro Suzuki Naoshi Dohmae Kojiro Mukai Tomohiko Taguchi
出版者: Japan Society for Cell Biology
雑誌: Cell Structure and Function (ISSN:03867196)
巻号頁・発行日: vol.48, no.1, pp.59-70, 2023 (Released:2023-02-16)
参考文献数: 43

Stimulator of interferon genes (STING) is an ER-localized transmembrane protein and the receptor for 2',3'-cyclic guanosine monophosphate–adenosine monophosphate (cGAMP), which is a second messenger produced by cGAMP synthase (cGAS), a cytosolic double-stranded DNA sensor. The cGAS-STING pathway plays a critical role in the innate immune response to infection of a variety of DNA pathogens through the induction of the type I interferons. Pharmacological activation of STING is a promising therapeutic strategy for cancer, thus the development of potent and selective STING agonists has been pursued. Here we report that mouse STING can be activated by phenylarsine oxide (PAO), a membrane permeable trivalent arsenic compound that preferentially reacts with thiol group of cysteine residue (Cys). The activation of STING with PAO does not require cGAS or cGAMP. Mass spectrometric analysis of the peptides generated by trypsin and chymotrypsin digestion of STING identifies several PAO adducts, suggesting that PAO covalently binds to STING. Screening of STING variants with single Cys to serine residues (Ser) reveals that Cys88 and Cys291 are critical to the response to PAO. STING activation with PAO, as with cGAMP, requires the ER-to-Golgi traffic and palmitoylation of STING. Our results identify a non-nucleotide STING agonist that does not target the cGAMP-binding pocket, and demonstrate that Cys of STING can be a novel target for the development of STING agonist.Key words: STING agonist, cysteine modification, innate immunity, phenylarsine oxide

2023-02-16 19:02:28
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1 0 0 0 OA A non-nucleotide agonist that binds covalently to cysteine residues of STING

著者: Kentaro Matsumoto Shenwei Ni Hiroyuki Arai Takashi Toyama Yoshiro Saito Takehiro Suzuki Naoshi Dohmae Kojiro Mukai Tomohiko Taguchi
出版者: Japan Society for Cell Biology
雑誌: Cell Structure and Function (ISSN:03867196)
巻号頁・発行日: pp.22085, (Released:2022-12-28)

Stimulator of interferon genes (STING) is an ER-localized transmembrane protein and the receptor for 2’,3’-cyclic guanosine monophosphate&endash;adenosine monophosphate (cGAMP), which is a second messenger produced by cGAMP synthase (cGAS), a cytosolic double-stranded DNA sensor. The cGAS-STING pathway plays a critical role in the innate immune response to infection of a variety of DNA pathogens through the induction of the type I interferons. Pharmacological activation of STING is a promising therapeutic strategy for cancer, thus the development of potent and selective STING agonists has been pursued. Here we report that mouse STING can be activated by phenylarsine oxide (PAO), a membrane permeable trivalent arsenic compound that preferentially reacts with thiol group of cysteine residue (Cys). The activation of STING with PAO does not require cGAS or cGAMP. Mass spectrometric analysis of the peptides generated by trypsin and chymotrypsin digestion of STING identifies several PAO adducts, suggesting that PAO covalently binds to STING. Screening of STING variants with single Cys to serine residues (Ser) reveals that Cys88 and Cys291 are critical to the response to PAO. STING activation with PAO, as with cGAMP, requires the ER-to-Golgi traffic and palmitoylation of STING. Our results identify a non-nucleotide STING agonist that does not target the cGAMP-binding pocket, and demonstrate that Cys of STING can be a novel target for the development of STING agonist.Key words: STING agonist, cysteine modification, innate immunity, phenylarsine oxide

2023-02-03 15:26:08
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1 0 0 0 OA Specific association of TBK1 with the trans-Golgi network following STING stimulation

著者: Haruka Kemmoku Yoshihiko Kuchitsu Kojiro Mukai Tomohiko Taguchi
出版者: Japan Society for Cell Biology
雑誌: Cell Structure and Function (ISSN:03867196)
巻号頁・発行日: pp.21080, (Released:2022-02-05)
被引用文献数: 13

Stimulator of interferon genes (STING) is essential for the type I interferon response induced by microbial DNA or self‐DNA leaked from mitochondria/nuclei. In response to the emergence of such DNAs in the cytosol, STING relocates from the endoplasmic reticulum (ER) to the Golgi, and activates TANK‐binding kinase 1 (TBK1), a cytosolic kinase essential for the activation of STING-dependent downstream signalling. To understand at which subcellular compartments TBK1 becomes associated with STING, we generated cells stably expressing fluorescent protein-tagged STING (mNeonGreen-STING) and TBK1 (TBK1-mScarletI). We found that after STING stimulation, TBK1 became associated with the trans‐Golgi network (TGN), not the other parts of the Golgi. STING variants that constitutively induce the type I interferon response have been identified in patients with autoinflammatory diseases named “STING-associated vasculopathy with onset in infancy (SAVI)”. Even in cells expressing these constitutively active STING variants, TBK1 was found to be associated with TGN, not the other parts of the Golgi. These results suggest that TGN acts as a specific platform where STING associates with and activates TBK1.Key words: the Golgi, membrane traffic, innate immunity, STING

2022-02-16 22:42:15
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