A missense mutation in the Arabidopsis COPII coat protein Sec24A induces the formation of clusters of the endoplasmic reticulum and Golgi apparatus.
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.
Faso
Carmen
C
Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.
Chen
Ya-Ni
YN
Tamura
Kentaro
K
Held
Michael
M
Zemelis
Starla
S
Marti
Lucia
L
Saravanan
RamuSubramanian
R
Hummel
Eric
E
Kung
Leslie
L
Miller
Elizabeth
E
Hawes
Chris
C
Brandizzi
Federica
F
D008841:Actin Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D022181:COP-Coated Vesicles / Q000378:metabolism / Q000648:ultrastructure*; D017124:Conserved Sequence / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure*; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D006056:Golgi Apparatus / Q000378:metabolism / Q000648:ultrastructure*; D007425:Intracellular Membranes / Q000378:metabolism / Q000473:pathology; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D020125:Mutation, Missense / Q000235:genetics*; D021381:Protein Transport / Q000235:genetics; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000235:genetics* / Q000378:metabolism
D029681:Arabidopsis Proteins; C547881:SEC24 protein, Arabidopsis; C530638:SEC24A protein, human; D033921:Vesicular Transport Proteins