Unconventional protein secretion.
It is generally believed that protein secretion or exocytosis is achieved via a conventional ER (endoplasmic reticulum)-Golgi-TGN (trans-Golgi network)-PM (plasma membrane) pathway in the plant endomembrane system. However, such signal peptide (SP)-dependent protein secretion cannot explain the increasing number of SP-lacking proteins which are found outside of the PM in plant cells. The process by which such leaderless secretory proteins (LSPs) gain access to the cell exterior is termed unconventional protein secretion (UPS) and has been well-studied in animal and yeast cells, but largely ignored by the plant community. Here, we review the evidence for UPS in plants especially in regard to the recently discovered EXPO (exocyst-positive-organelle).
School of Life Sciences, Centre for Cell and Developmental Biology, the Chinese University of Hong Kong, Hong Kong, China.
Yu
Y
Ding
Juan
J
Wang
Junqi
J
Wang
York-Dieter
YD
Stierhof
David G
DG
Robinson
Liwen
L
Jiang
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D055354:Exosomes / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D008322:Mammals / Q000378:metabolism; D059828:Plant Cells / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D021382:Protein Sorting Signals; D021381:Protein Transport; D055571:Secretory Pathway; D014617:Vacuoles / Q000378:metabolism; D015003:Yeasts / Q000378:metabolism
D010940:Plant Proteins; D021382:Protein Sorting Signals