Localization of plasma membrane t-SNAREs syntaxin 2 and 3 in intracellular compartments.
BACKGROUND
Membrane fusion requires the formation of a complex between a vesicle protein (v-SNARE) and the target membrane proteins (t-SNAREs). Syntaxin 2 and 3 are t-SNAREs that, according to previous over-expression studies, are predominantly localized at the plasma membrane. In the present study we investigated localization of the endogenous syntaxin 2 and 3.


RESULTS
Endogenous syntaxin 2 and 3 were found in NRK cells in intracellular vesicular structures in addition to regions of the plasma membrane. Treatment of these cells with N-ethylmaleimide (NEM), which is known to inactivate membrane fusion, caused syntaxin 3 to accumulate in the trans-Golgi network and syntaxin 2 in perinuclear membrane vesicles. Kinetic analysis in the presence of NEM indicated that this redistribution of syntaxin 2 and 3 takes place via actin containing structures.


CONCLUSIONS
Our data suggest that syntaxin 2 cycles between the plasma membrane and the perinuclear compartment whereas syntaxin 3 cycles between the plasma membrane and the trans-Golgi network. It is possible that this cycling has an important role in the regulation of t-SNARE function.
Band
Arja M
AM
Haartman Institute, Biomedicum Helsinki, Haartmaninkatu 8, 00014 University of Helsinki, Finland. arja.band@helsinki.fi
Kuismanen
Esa
E
D000199:Actins; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D005033:Ethylmaleimide / Q000494:pharmacology; D006056:Golgi Apparatus / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism*; D008561:Membrane Fusion / Q000187:drug effects; D008565:Membrane Proteins / Q000378:metabolism*; D021381:Protein Transport; D050765:Qa-SNARE Proteins / Q000378:metabolism*; D051381:Rats; D050600:SNARE Proteins / Q000378:metabolism; D050827:Syntaxin 1 / Q000378:metabolism*
D000199:Actins; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; D050827:Syntaxin 1; D005033:Ethylmaleimide