A Missense Mutation in the Arabidopsis COPII Coat Protein Sec24A Induces the Formation of Clusters of the Endoplasmic Reticulum and Golgi Apparatus |
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| Authors: | Carmen Faso Ya-Ni Chen Kentaro Tamura Michael Held Starla Zemelis Lucia Marti RamuSubramanian Saravanan Eric Hummel Leslie Kung Elizabeth Miller Chris Hawes Federica Brandizzi |
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| Institution: | aMichigan State University–Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824;bSchool of Life Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom;cDepartment of Biological Sciences, Columbia University, New York, New York 10027 |
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| Abstract: | How the endoplasmic reticulum (ER) and the Golgi apparatus maintain their morphological and functional identity while working in concert to ensure the production of biomolecules necessary for the cell''s survival is a fundamental question in plant biology. Here, we isolated and characterized an Arabidopsis thaliana mutant that partially accumulates Golgi membrane markers and a soluble secretory marker in globular structures composed of a mass of convoluted ER tubules that maintain a connection with the bulk ER. We established that the aberrant phenotype was due to a missense recessive mutation in sec24A, one of the three Arabidopsis isoforms encoding the coat protomer complex II (COPII) protein Sec24, and that the mutation affects the distribution of this critical component at ER export sites. By contrast, total loss of sec24A function was lethal, suggesting that Arabidopsis sec24A is an essential gene. These results produce important insights into the functional diversification of plant COPII coat components and the role of these proteins in maintaining the dynamic identity of organelles of the early plant secretory pathway. |
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