Abstract
Ca(2+) import into the lumen of the trans-Golgi network (TGN) by the secretory pathway calcium ATPase1 (SPCA1) is required for the sorting of secretory cargo. How is Ca(2+) retained in the lumen of the Golgi, and what is its role in cargo sorting? We show here that a soluble, lumenal Golgi resident protein, Cab45, is required for SPCA1-dependent Ca(2+) import into the TGN; it binds secretory cargo in a Ca(2+)-dependent reaction and is required for its sorting at the TGN.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Calcium / metabolism*
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Calcium Signaling*
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Calcium-Binding Proteins / genetics
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Calcium-Binding Proteins / metabolism*
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Cartilage Oligomeric Matrix Protein
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Cathepsin D / metabolism
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Extracellular Matrix Proteins / metabolism
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Gene Knockdown Techniques
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Glycoproteins / genetics
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Glycoproteins / metabolism*
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HeLa Cells
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Homeostasis
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Humans
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Matrilin Proteins
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Protein Binding
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Protein Isoforms / genetics
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Protein Isoforms / metabolism
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Protein Transport
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RNA Interference
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Secretory Pathway*
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trans-Golgi Network / metabolism*
Substances
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Calcium-Binding Proteins
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Cartilage Oligomeric Matrix Protein
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Extracellular Matrix Proteins
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Glycoproteins
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Matrilin Proteins
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Protein Isoforms
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TSP5 protein, human
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SDF4 protein, human
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CTSD protein, human
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Cathepsin D
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Calcium