Peroxicretion: a novel secretion pathway in the eukaryotic cell.
BACKGROUND
Enzyme production in microbial cells has been limited to secreted enzymes or intracellular enzymes followed by expensive down stream processing. Extracellular enzymes consists mainly of hydrolases while intracellular enzymes exhibit a much broader diversity. If these intracellular enzymes could be secreted by the cell the potential of industrial applications of enzymes would be enlarged. Therefore a novel secretion pathway for intracellular proteins was developed, using peroxisomes as secretion vesicles.


RESULTS
Peroxisomes were decorated with a Golgi derived v-SNARE using a peroxisomal membrane protein as an anchor. This allowed the peroxisomes to fuse with the plasma membrane. Intracellular proteins were transported into the peroxisomes by adding a peroxisomal import signal (SKL tag). The proteins which were imported in the peroxisomes, were released into the extra-cellular space through this artificial secretion pathway which was designated peroxicretion. This concept was supported by electron microscopy studies.


CONCLUSIONS
Our results demonstrate that it is possible to reroute the intracellular trafficking of vesicles by changing the localisation of SNARE molecules, this approach can be used in in vivo biological studies to clarify the different control mechanisms regulating intracellular membrane trafficking. In addition we demonstrate peroxicretion of a diverse set of intracellular proteins. Therefore, we anticipate that the concept of peroxicretion may revolutionize the production of intracellular proteins from fungi and other microbial cells, as well as from mammalian cells.
Sagt
Cees M J
CM
DSM Biotechnology Center, Beijerinck Laboratory, PO Box 1, 2600MA Delft, the Netherlands. cees.sagt@dsm.com
ten Haaft
Peter J
PJ
Minneboo
Ingeborg M
IM
Hartog
Miranda P
MP
Damveld
Robbert A
RA
van der Laan
Jan Metske
JM
Akeroyd
Michiel
M
Wenzel
Thibaut J
TJ
Luesken
Francisca A
FA
Veenhuis
Marten
M
van der Klei
Ida
I
de Winde
Johannes H
JH
D001234:Aspergillus niger / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000378:metabolism*; D021381:Protein Transport; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D050600:SNARE Proteins / Q000378:metabolism*; D055571:Secretory Pathway
D008565:Membrane Proteins; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D050600:SNARE Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins