Secretory cargo sorting at the trans-Golgi network.
Sorting of proteins for secretion from cells is crucial for normal physiology and the regulation of key cellular events. Although the sorting of lysosomal hydrolases at the trans-Golgi network (TGN) for delivery to pre-lysosomes is well characterized, the corresponding mechanism by which secreted proteins are sorted for plasma-membrane delivery remains poorly understood. Recent discoveries have revealed a novel sorting mechanism that requires the linkage between the cytoplasmic actin cytoskeleton to the membrane-anchored Ca(2+) ATPase, SPCA1 (secretory pathway calcium ATPase 1), and the luminal 45 kDa Ca(2+)-binding protein, Cab45, for successful sorting of a subset of proteins at the TGN. We review progress in understanding these processes.
Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
Christine
C
Kienzle
Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany. Electronic address: vonblume@biochem.mpg.de.
Julia
J
von Blume
D008841:Actin Cytoskeleton / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D055571:Secretory Pathway / Q000502:physiology*; D021601:trans-Golgi Network / Q000378:metabolism*
Ca(2+); TGN; protein sorting; secretory cargo