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Yokoyama T, Yamamoto Y, Hirakawa M, Kato K, Saino T. Vesicular nucleotide transporter-immunoreactive type I cells associated with P2X3-immunoreactive nerve endings in the rat carotid body. J Comp Neurol 2019; 528:1486-1501. [PMID: 31808543 DOI: 10.1002/cne.24837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/21/2019] [Accepted: 12/02/2019] [Indexed: 12/23/2022]
Abstract
ATP is the major excitatory transmitter from chemoreceptor type I cells to sensory nerve endings in the carotid body, and has been suggested to be released by exocytosis from these cells. We investigated the mRNA expression and immunohistochemical localization of vesicular nucleotide transporter (VNUT) in the rat carotid body. RT-PCR detected mRNA expression of VNUT in extracts of the tissue. Immunoreactivity for VNUT was localized in a part of type I cells immunoreactive for synaptophysin (SYN), but not in glial-like type II cells immunoreactive for S100 and S100B. Among SYN-immunoreactive type I cells, VNUT immunoreactivity was selectively localized in the sub-population of tyrosine hydroxylase (TH)-immunorective type I cells associated with nerve endings immunoreactive for the P2X3 purinoceptor; however, it was not detected in the sub-population of type I cells immunoreactive for dopamine beta-hydroxylase. Multi-immunolabeling for VNUT, P2X3, and Bassoon revealed that Bassoon-immunoreactive products were localized in type I cells with VNUT immunoreactivity, and accumulated on the contact side of P2X3-immunoreactive nerve endings. These results revealed the selective localization of VNUT in the subpopulation of TH-immunoreactive type I cells attached to sensory nerve endings and suggested that these cells release ATP by exocytosis for chemosensory transmission in the carotid body.
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Affiliation(s)
- Takuya Yokoyama
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Masato Hirakawa
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan
| | - Kouki Kato
- Center for Laboratory Animal Science, National Defense Medical College, Tokorozawa, Japan
| | - Tomoyuki Saino
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan
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Saegusa S, Fukaya M, Kakegawa W, Tanaka M, Katsumata O, Sugawara T, Hara Y, Itakura M, Okubo T, Sato T, Yuzaki M, Sakagami H. Mice lacking EFA6C/Psd2, a guanine nucleotide exchange factor for Arf6, exhibit lower Purkinje cell synaptic density but normal cerebellar motor functions. PLoS One 2019; 14:e0216960. [PMID: 31095630 PMCID: PMC6522047 DOI: 10.1371/journal.pone.0216960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/01/2019] [Indexed: 11/18/2022] Open
Abstract
ADP ribosylation factor 6 (Arf6) is a small GTPase that regulates various neuronal events including formation of the axon, dendrites and dendritic spines, and synaptic plasticity through actin cytoskeleton remodeling and endosomal trafficking. EFA6C, also known as Psd2, is a guanine nucleotide exchange factor for Arf6 that is preferentially expressed in the cerebellar cortex of adult mice, particularly in Purkinje cells. However, the roles of EFA6C in cerebellar development and functions remain unknown. In this study, we generated global EFA6C knockout (KO) mice using the CRISPR/Cas9 system and investigated their cerebellar phenotypes by histological and behavioral analyses. Histological analyses revealed that EFA6C KO mice exhibited normal gross anatomy of the cerebellar cortex, in terms of the thickness and cellularity of each layer, morphology of Purkinje cells, and distribution patterns of parallel fibers, climbing fibers, and inhibitory synapses. Electron microscopic observation of the cerebellar molecular layer revealed that the density of asymmetric synapses of Purkinje cells was significantly lower in EFA6C KO mice compared with wild-type control mice. However, behavioral analyses using accelerating rotarod and horizontal optokinetic response tests failed to detect any differences in motor coordination, learning or adaptation between the control and EFA6C KO mice. These results suggest that EFA6C plays ancillary roles in cerebellar development and motor functions.
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Affiliation(s)
- Shintaro Saegusa
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Masahiro Fukaya
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Wataru Kakegawa
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Manabu Tanaka
- Bio-imaging Center, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Osamu Katsumata
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Takeyuki Sugawara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Yoshinobu Hara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Tadashi Okubo
- Department of Laboratory Animal Science, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Toshiya Sato
- Department of Laboratory Animal Science, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
- * E-mail:
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Ratcliffe CDH, Siddiqui N, Coelho PP, Laterreur N, Cookey TN, Sonenberg N, Park M. HGF-induced migration depends on the PI(3,4,5)P 3-binding microexon-spliced variant of the Arf6 exchange factor cytohesin-1. J Cell Biol 2018; 218:285-298. [PMID: 30404949 PMCID: PMC6314551 DOI: 10.1083/jcb.201804106] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 09/19/2018] [Accepted: 10/17/2018] [Indexed: 12/19/2022] Open
Abstract
Splice variants of the Arf6 guanine exchange factor cytohesin-1 display differential affinity for PI(4,5)P2 and PI(3,4,5)P3. Ratcliffe et al. show that the specific lipid binding of the diglycine variant of cytohesin-1 is needed for HGF-dependent cell migration and establishment of the leading edge, thereby regulating cancer cell migration following activation of the proto-oncogenic receptor tyrosine kinase Met. Differential inclusion or skipping of microexons is an increasingly recognized class of alternative splicing events. However, the functional significance of microexons and their contribution to signaling diversity is poorly understood. The Met receptor tyrosine kinase (RTK) modulates invasive growth and migration in development and cancer. Here, we show that microexon switching in the Arf6 guanine nucleotide exchange factor cytohesin-1 controls Met-dependent cell migration. Cytohesin-1 isoforms, differing by the inclusion of an evolutionarily conserved three-nucleotide microexon in the pleckstrin homology domain, display differential affinity for PI(4,5)P2 (triglycine) and PI(3,4,5)P3 (diglycine). We show that selective phosphoinositide recognition by cytohesin-1 isoforms promotes distinct subcellular localizations, whereby the triglycine isoform localizes to the plasma membrane and the diglycine to the leading edge. These data highlight microexon skipping as a mechanism to spatially restrict signaling and provide a mechanistic link between RTK-initiated phosphoinositide microdomains and Arf6 during signal transduction and cancer cell migration.
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Affiliation(s)
- Colin D H Ratcliffe
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Nadeem Siddiqui
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Paula P Coelho
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Nancy Laterreur
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
| | - Tumini N Cookey
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
| | - Nahum Sonenberg
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Morag Park
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada .,Department of Biochemistry, McGill University, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Oncology, McGill University, Montreal, Quebec, Canada
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Chomphoo S, Pakkarato S, Sawatpanich T, Sakagami H, Kondo H, Hipkaeo W. Localization of EFA6 (exchange factor for ARF6) isoform D in steroidogenic testicular Leydig cells of adult mice. Acta Histochem 2018; 120:263-268. [PMID: 29496264 DOI: 10.1016/j.acthis.2018.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 02/03/2018] [Accepted: 02/21/2018] [Indexed: 11/19/2022]
Abstract
EFA6 (exchange factor for ARF6) activates Arf6 (ADP ribosylation factor 6) by exchanging ADP to ATP and the resulting activated form of Arf6 is involved in the membrane trafficking and actin remodeling of cells. Our previous study has shown the selective expression/localization of EFA6D in steroidogenic adrenocortical cells in situ of adult mice. In view of the previous finding, the present study was undertaken to examine its localization in mouse Leydig cells representing another steroidogenic cell species in order to further support the possible involvement of the EFA6/Arf6 cascade via membrane trafficking in the regulation of steroidogenesis and/or secretion. A distinct band for EFA6D with the same size as that of the brain was detected in the testis of adult mice. In immuno-light microscopy, immunoreactivity for EFA6D was seen throughout the cytoplasm in most Leydig cells without any distinct accumulation along the plasmalemma. Lack of immunoreactivity for EFA6D was seen in the seminiferous tubular epithelium. In immuno-electron microscopy, the immune-labeling was seen in sporadic/focal patterns on plasma membranes and some vesicles and vacuoles subjacent to the plasma membranes. More constant and rather predominant is the labeling on numerous mitochondria. No immuno-labeling was seen in lipid droplets. The present study suggests that EFA6D is somehow involved in regulation of the synthesis and/or secretion of testosterone through the membrane-traffic by activation of Arf6. In addition, EFA6D is suggested to play in mitochondria some yet unidentified roles rather independent of Arf6-activation, which remains to be elucidated.
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Affiliation(s)
- Surang Chomphoo
- Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Sawetree Pakkarato
- Department of Social Sciences, Faculty of Sciences and Liberal Arts, Rajamangala University of Technology Isan, Sura Narai Rd, Nai-muang, Muang, Nakhon Ratchasima 30000, Thailand
| | - Tarinee Sawatpanich
- Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Hiroyuki Sakagami
- Department of Anatomy, School of Medicine, Kitasato University, Tokyo, Japan
| | - Hisatake Kondo
- Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Wiphawi Hipkaeo
- Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand.
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Tachow A, Thoungseabyoun W, Phuapittayalert L, Petcharat K, Sakagami H, Kondo H, Hipkaeo W. Co-localization of endogenous Arf6 and its activator EFA6D in the granular convoluted tubule cells of mouse submandibular glands under normal conditions and when stimulated by isoproterenol, noradrenaline and carbachol. Arch Oral Biol 2017. [PMID: 28645101 DOI: 10.1016/j.archoralbio.2017.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE This study proposed to investigate the localization at light and electron microscopic levels of Arf6 and its activator EFA6D in the mouse submandibular gland (SMG) under normal conditions and when stimulated by adrenergic or cholinergic agonists. MATERIALS AND METHODS SMGs of male adult mice were utilized for immunoblotting and immuno-light and -electron microscopic analyses. Isoproterenol and noradrenalin were used as adrenergics, while carbachol was used for the cholinergic stimulant. SMGs were examined at 15, 30, 60 and 120min after intraperitoneal injection of these agents. RESULTS Immunoreactivities for both Arf6 and its activator EFA6D were similarly intense in the basolateral domain of GCTs, but no significant immunoreactivities were seen in the apical domain of GCT cells or any domain of acinar cells under normal conditions. In immuno-electron microscopy, the immunoreactive materials were mainly deposited on the basolateral plasma membranes and subjacent cytoplasm. Shortly after injection of isoproterenol and noradrenaline, but not carbachol, the immunoreactivities for both molecules were additionally seen on the apical plasmalemma of most, if not all, GCT cells, but not acinar cells. CONCLUSION The present findings suggest that the direct involvement of Arf6/EFA6D in regulatory exocytosis at the apical plasma membrane of acinar and GCT cells is apparently to be smaller, if present, than that of endocytosis at the basolateral membranes of GCT cells under normal conditions. This also suggests that the two molecules function additionally at the apical membrane of GCT cells for modulation of saliva secretion under β-adrenoceptor stimulation.
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Affiliation(s)
- Apussara Tachow
- Nanomorphology-Based Apply Research Group & Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Wipawee Thoungseabyoun
- Nanomorphology-Based Apply Research Group & Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | | | - Kanoktip Petcharat
- Biochemistry and Nutrition, School of Medical Science, University of Phayao, Phayao, Thailand
| | - Hiroyuki Sakagami
- Department of Anatomy, School of Medicine, Kitasato University, Tokyo, Japan
| | - Hisatake Kondo
- Nanomorphology-Based Apply Research Group & Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Department of Organ Anatomy, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Wiphawi Hipkaeo
- Nanomorphology-Based Apply Research Group & Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
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