title: Subclass-specific localization and trafficking of Arabidopsis p24 proteins in the ER-Golgi interface.
abstract: We describe a comprehensive analysis of the subcellular localization and in vivo trafficking of Arabidopsis p24 proteins. In Arabidopsis, there are 11 p24 proteins, which fall into only δ and β subfamilies. Interestingly, the δ subfamily of p24 proteins in Arabidopsis is elaborated spectacularly in evolution, which can be grouped into two subclasses: p24δ1 and p24δ2. We found that, although all p24δ proteins possess classic COPII/COPI binding motifs in their cytosolic C-termini, p24δ1 proteins are localized to the endoplasmic reticulum (ER), p24δ2 proteins are localized to both ER and Golgi. Two p24β proteins reside largely in Golgi. Similar to Atp24 (termed p24δ1c in this study), p24δ2d also cycles between the ER and Golgi. Interestingly, coexpression with p24β1 could retain p24δ2d, but not p24δ1d in Golgi. We revealed that the lumenal coiled-coil domain of p24δ2d is required for its steady-state localization in Golgi, probably through its interaction with p24β1. In p24β1, there is no classic COPII or COPI binding motif in its C-terminus. However, the protein also cycles between the ER and Golgi. We found that a conserved RV motif located at the extreme end of the C-terminus of p24β1 plays an important role in its Golgi target.
authors: Developmental Biology Research Initiatives, Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, Quebec, H3A 1B1, Canada.
authors: Jun
authors: J
authors: Chen
authors: Xingyun
authors: X
authors: Qi
authors: Huanquan
authors: H
authors: Zheng
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000145:classification* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism*; D061146:Chlorophyll Binding Proteins / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D021381:Protein Transport; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D061146:Chlorophyll Binding Proteins; C529795:Lhcb6 protein, Arabidopsis