Akiko K Satoh's Lab

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Research

Synthesis, transport and sorting of transmembrane proteins in Drosophila Photoreceptor

Fully differentiated cells are often highly polarized in vivo; epithelial cells and neurons are two well-known examples. Epithelial cells contain apical and basolateral plasma membrane domains, while neurons contain an axon, dendrites, and a cell body. Polarized vesicle transport is essential for establishing and maintaining these polarized structures. However, the underlying mechanisms are not well elucidated. Highly polarized fly photoreceptors are a good genetics-based model for studying the mechanism of polarized transport. In a single plane of the retina, 3 distinct plasma membrane domains of many photoreceptors can be observed. The first domain is the photoreceptive membrane domain, i.e., the rhabdomere, which is formed at the center of the apical plasma membrane during pupal development. Proteins involved in photo-transduction—such as the photosensitive molecule rhodopsin1 (Rh1) and the Ca2+ permeable channel TRP—as well as a protein essential for rhabdomere architecture, chaoptin (Chp), specifically localize in the rhabdomeres. The second domain is the peripheral apical domain surrounding the rhabdomere, i.e., the stalk membrane, which is where the apical determinant Crb is localized. The third domain is the basolateral membrane, which is separated from the apical membrane by the adherens junctions. Na+K+ATPase localizes on the basolateral membrane, similar to typical polarized epithelial cells.

 One of the advantages of the Drosophila melanogaster model is that forward genetics can be used for genome-wide screening. Thus, to identify the genes essential for polarized membrane transport to the rhabdomeres, we performed retinal mosaic screening using the FLP/FRT method with in vivo fluorescent imaging of Arrestin2::GFP, which specifically found to activated Rh1. We found several important key players for Rh1 synthesis and transport toward the rhabdomeres: please look at the published papers.

Akiko K Satoh, Associate Professor, Hiroshima University

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Publications

(Updated 2016/10)

Original articles

  1. Satoh T, Nakamura Y, Satoh AK. (2016) The roles of Syx5 in Golgi morphology and Rhodopsin transport in Drosophila photoreceptors., Biol Open. 2016 Oct 15;5(10):1420-1430.
  2. Satoh T, Nakamura Y, Satoh AK. (2016) Rab6 functions in polarized transport in Drosophila photoreceptors., Fly (Austin). 2016 Jul 2;10(3):123-7. Epub 2016 Apr 26
  3. Iwanami N#, Nakamura Y#, Satoh T#, Liu Z, Satoh AK. (#: contributed equally) (2016) Rab6 Is Required for Multiple Apical Transport Pathways but Not the Basolateral Transport Pathway in Drosophila Photoreceptors., PLoS Genet. 2016 Feb 18;12(2).
  4. Satoh T#, Ohba A, Liu Z, Inagaki T, Satoh AK. (2015) dPob/EMC is essential for biosynthesis of rhodopsin and other multi-pass membrane proteins in Drosophila photoreceptors., Elife. 2015 Feb 26;4.
  5. Satoh, T., Inagaki, T., Liu, J., Watanabe, R. and Satoh, A. K. (2013) GPI biosynthesis is essential for Rhodopsin sorting at the trans-Golgi network in Drosophila photoreceptors., Development 140, 385-94.
  6. Hardie, R. C., Satoh, A. K. and Liu, C-H.(2012) Regulation of arrestin translocation by Ca2+ and Myosin III in Drosophila photoreceptors., J. Neurosci., 32, 9205-16 Open Access
  7. Satoh, A. K.#, Xia, H.#, Yan, L., Huang J., Hardie R. C. and Ready, D. F. (#: contributed equally) (2010) Arrestin translocation is stoichiometric to rhodopsin isomerization and accelerated by phototransduction in Drosophila photoreceptors., Neuron 67, 997-1008.
  8. Liu, C-H., Satoh, A. K., Postma, M., Huang J., Ready, D. F. and Hardie R. C. (2008) Ca2+ dependent Metarhodopsin inactivation mediated by calmodulin and NINAC Myosin III. Neuron. 59, 778-789.
  9. Satoh, A. K., Li, B., Xia, H. and Ready D. F. (2008) Calcium-activated Myosin V closes the Drosophila pupil. Current Biology. 18, 951-955.
  10. Li, B.#, Satoh, A. K.# and Ready D. F. (#: contributed equally) (2007) Myosin-V, Rab11 and dRip11 direct apical secretion and cellular morphogenesis in developing Drosophila photoreceptors J. Cell Biol. 177, 659-69.
  11. Satoh, A. K. and Ready D. F. (2005) Arrestin1 mediates light-dependent endocytosis and cell survival. Current Biology. 15, 1722-33.
  12. Satoh, A. K., O’Tousa J. E., Ozaki, K. and Ready D. F. (2005) Rab11 mediates post-Golgi trafficking of rhodopsin to the photosensitive apical membrane of Drosophila photoreceptors. Development. 132, 1487-97.
  13. Fujikawa K, Satoh, A. K., Kawamura S. and Ozaki K. (2002) Molecular and functional characterization of a unique Rab protein, RABRP1, containing the WDIAGQE sequence in a GTPase motif. Zoological Science. 19, 981-993.
  14. Satoh, A. K., Nagatani H., Tokunaga, F., Kawamura S. and Ozaki K. (1998) Rhodopsin transport and Rab expression in the carotenoid-deprived Drosophila melanogaster. Zoological Science. 15, 651-659.
  15. Satoh, A. K., Tokunaga, F., Kawamura, S. and Ozaki, K. (1997) In situ inhibition of vesicle transport and protein processing in the dominant negative Rab1 mutant of Drosophila. Journal of Cell Science. 110, 2943-2853.
  16. Satoh, A. K., Tokunaga, F. and Ozaki, K. (1997) Rab proteins of Drosophila melanogaster: novel members of the Rab-protein family. FEBS Letter. 404, 65-69.