title: A new role for annexin A11 in the early secretory pathway via stabilizing Sec31A protein at the endoplasmic reticulum exit sites (ERES).
abstract: Exit of cargo molecules from the endoplasmic reticulum (ER) for transport to the Golgi is the initial step in intracellular vesicular trafficking. The coat protein complex II (COPII) machinery is recruited to specialized regions of the ER, called ER exit sites (ERES), where it plays a central role in the early secretory pathway. It has been known for more than two decades that calcium is an essential factor in vesicle trafficking from the ER to Golgi apparatus. However, the role of calcium in the early secretory pathway is complicated and poorly understood. We and others previously identified Sec31A, an outer cage component of COPII, as an interacting protein for the penta-EF-hand calcium-binding protein ALG-2. In this study, we show that another calcium-binding protein, annexin A11 (AnxA11), physically associates with Sec31A by the adaptor function of ALG-2. Depletion of AnxA11 or ALG-2 decreases the population of Sec31A that is stably associated with the ERES and causes scattering of juxtanuclear ERES to the cell periphery. The synchronous ER-to-Golgi transport of transmembrane cargoes is accelerated in AnxA11- or ALG-2-knockdown cells. These findings suggest that AnxA11 maintains architectural and functional features of the ERES by coordinating with ALG-2 to stabilize Sec31A at the ERES.
authors.affiliation: From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan and. Electronic address: shibabou@agr.nagoya-u.ac.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Shibata
authors.affiliation: From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan and.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kanadome
authors.affiliation: From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan and.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Sugiura
authors.affiliation: From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan and.
authors.forename: Takeru
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan and.
authors.forename: Minami
authors.initials: M
authors.lastname: Yamamuro
authors.affiliation: the Department of Cell Biology, UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, United Kingdom.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Moss
authors.affiliation: From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan and.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Maki
mesh_terms: D017302:Annexins / Q000235:genetics / Q000378:metabolism*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D001693:Biological Transport, Active / Q000502:physiology; D022181:COP-Coated Vesicles / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism*; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D055550:Protein Stability; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D017302:Annexins; D051017:Apoptosis Regulatory Proteins; D002135:Calcium-Binding Proteins; C097753:PDCD6 protein, human; C507455:SEC31A protein, human; D033921:Vesicular Transport Proteins; D002118:Calcium
keywords: Annexin; Calcium-binding Protein; Endoplasmic Reticulum (ER); Fluorescence Recovery after Photobleaching (FRAP); Membrane Trafficking; Protein-Protein Interaction