Akira Kato
Akira Kato

Associate Professor, Center for Biological Resources & Informatics
PhD 1998, Tokyo Institute of Technology
E-mail: akirkato(at)bio.titech.ac.jp
Office: Room 522, B2 building, Suzukakedai campus

Areas of Research: Molecular and cellular biology, epithelial transport, animal physiology, transporter biology, comparative and evolutionary physiology, comparative genomics

Keywords: Solute carrier, ion channel, water and electrolyte homeostasis, hormonal regulation, electrophysiology, environmental adaptation, Na+/NH4+ exchanger, Na+-Cl- cotransporter, Na+/Mg2+ exchanger, Cl--SO42- exchanger, H+-Cl- cotransporter, renal tubule, intestinal epithelium, ionocyte

Research interest:

Vertebrate genomes contain ~1,200 genes encoding membrane transport proteins such as solute carriers, channels, ABC transporters, and pumps (Hediger et al., Mol. Aspects Med. 34: 95-107, 2013). These families involve many proteins whose activity and physiological function are not well understood (César-Razquin et al., Cell 162: 478-487, 2015). The basic composition and number of these genes are relatively well conserved among the genomes of vertebrate species such as mammals, amphibians and fishes, while deletions or duplications of the family members are often observed in specific species or lineages. By comparing the expression pattern of each gene family in some species and analyzing the activities of their products, we explore novel thermodynamically-consistent mechanisms of epithelial transport. We are now focusing on transporters involved in renal excretion of divalent ions (Mg2+, SO42- and Ca2+) in seawater fish (Fig.1), renal excretion of water in freshwater fish, and branchial absorption of monovalent ions (Na+ and Cl-) in freshwater fish (Fig.2).


Fig.1. Water and electrolyte homeostasis of marine teleosts


Fig.2. Water and electrolyte homeostasis of freshwater teleosts

Selected publications

  1. Hasegawa, K., Kato, A., Watanabe, T., Takagi, W., Romero, M.F., Bell, J.D., Toop, T., Donald, J.A., Hyodo, S. (2016) Sulfate transporters involved in sulfate secretion in the kidney are localized in the renal proximal tubule II of the elephant fish (Callorhinchus milii). Am. J. Physiol. Regul. Integr. Comp. Physiol. 311: R66-R178
  2. Chintapalli, V.R., Kato, A., Henderson, L., Hirata, T., Woods, D.J., Overend, G., Davies, S.A., Romero, M.F., and Dow, J.A.T. (2015) Transport proteins NHA1 and NHA2 are essential for survival, but have distinct transport modalities. Proc. Natl. Acad. Sci. U. S. A. 112: 11720-11725.
  3. Nag, K., Sultana, N., Kato, A., Dranik, A., Nakamura, N., Kutsuzawa, K., Hirose, S., and Akaike, T. (2015) Ligand-induced internalization, recycling, and resensitization of adrenomedullin receptors depend not on CLR or RAMP alone but on the receptor complex as a whole. Gen. Comp. Endocrinol. 212: 156-162.
  4. Islam, Z., Hayashi, N., Inoue, H., Umezawa, T., Kimura, Y., Doi, H., Romero, M.F., Hirose, S., and Kato, A. (2014) Identification and lateral membrane localization of cyclin M3, likely to be involved in renal Mg2+ handling in seawater fish. Am. J. Physiol. Regul. Integr. Comp. Physiol. 307: R525-R537.
  5. Ito, Y., Kato, A., Hirata, T., Hirose, S., and Romero, M.F. (2014) Na+/H+ and Na+/NH4+ exchange activities of zebrafish NHE3b expressed in Xenopus oocytes. Am. J. Physiol. Regul. Integr. Comp. Physiol. 306: R315-R327.
  6. Fukuda, H., Hirata, T., Nakamura, N., Kato, A., Kawahara, K., Wakabayashi, S., Chang, M.H., Romero, M.F., and Hirose, S. (2013) Identification and properties of a novel variant of NBC4 (Na+/HCO3- co-transporter 4) that is predominantly expressed in the choroid plexus. Biochem. J. 450: 179-187.
  7. Fukuzawa, T., Ishida, J., Kato, A., Ichinose, T., Ariestanti, D.M., Takahashi, T., Ito, K., Abe, J., Suzuki, T., Wakana, S., Fukamizu, A., Nakamura, N., and Hirose, S. (2013) Lung Surfactant Levels are Regulated by Ig-Hepta/GPR116 by Monitoring Surfactant Protein D. PLoS One 8: e69451.
  8. Islam, Z., Hayashi, N., Yamamoto, Y., Doi, H., Romero, M.F., Hirose, S., and Kato, A. (2013) Identification and proximal tubular localization of the Mg2+ transporter, Slc41a1, in a seawater fish. Am. J. Physiol. Regul. Integr. Comp. Physiol. 305: R385-R396.
  9. Li, S., Kato, A., Takabe, S., Chen, A.P., Romero, M.F., Umezawa, T., Nakada, T., Hyodo, S., and Hirose, S. (2013) Expression of a novel isoform of Na+/H+ exchanger 3 in the kidney and intestine of banded houndshark, Triakis scyllium. Am. J. Physiol. Regul. Integr. Comp. Physiol. 304: R865-R876
  10. Umezawa, T., Kato, A., Ogoshi, M., Ookata, K., Munakata, K., Yamamoto, Y., Islam, Z., Doi, H., Romero, M.F., and Hirose, S. (2012) O2-filled swimbladder employs monocarboxylate transporters for the generation of O2 by lactate-induced root effect hemoglobin. PLoS One 7: e34579.
  11. Munakata, K., Ookata, K., Doi, H., Baba, O., Terashima, T., Hirose, S., and Kato, A. (2012) Histological demonstration of glucose transporters, fructose-1,6-bisphosphatase, and glycogen in gas gland cells of the swimbladder: is a metabolic futile cycle operating? Biochem. Biophys. Res. Commun. 417: 564-569.
  12. Chang, M.H., Plata, C., Kurita, Y., Kato, A., Hirose, S., and Romero, M.F. (2012) Euryhaline pufferfish NBCe1 differs from nonmarine species NBCe1 physiology. Am. J. Physiol. Cell Physiol. 302: C1083-C1095.
  13. Kato, A., Muro, T., Kimura, Y., Li, S., Islam, Z., Ogoshi, M., Doi, H., and Hirose, S. (2011) Differential expression of Na+-Cl- cotransporter and Na+-K+-Cl- cotransporter 2 in the distal nephrons of euryhaline and seawater pufferfishes. Am. J. Physiol. Regul. Integr. Comp. Physiol. 300: R284-R297.
  14. Islam, Z., Kato, A., Romero, M.F., and Hirose, S. (2011) Identification and apical membrane localization of an electrogenic Na+/Ca2+ exchanger NCX2a likely to be involved in renal Ca2+ excretion by seawater fish. Am. J. Physiol. Regul. Integr. Comp. Physiol. 301: R1427-R1439.

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