Syntaxin 18, a SNAP receptor that functions in the endoplasmic reticulum, intermediate compartment, and cis-Golgi vesicle trafficking.
Members of the syntaxin family are target-soluble N-ethylmaleimide-sensitive factor-attachment protein receptors involved in vesicle docking and/or fusion within the exocytic and endocytotic pathways. By using the yeast two-hybrid system, we have identified a novel member of the syntaxin family, syntaxin 18, that binds to alpha-soluble N-ethylmaleimide-sensitive factor-attachment protein. Subcellular fractionation and immunocytochemical analysis revealed that syntaxin 18 is principally located in the endoplasmic reticulum. We examined the effect of overexpression of FLAG-tagged syntaxin 18 and a mutant lacking the N-terminal 81 amino acid residues on protein transport and organelles in the early secretory pathway. Both expressed proteins localized to the endoplasmic reticulum, and the expressed FLAG-syntaxin 18 caused remarkable aggregation of endoplasmic reticulum membranes. Although expression of the FLAG-syntaxin 18 lacking the N-terminal region produced less effect on the morphology of the endoplasmic reticulum, dispersion of the endoplasmic reticulum-Golgi intermediate compartment and cis-Golgi was elicited. Moreover, overexpression of the FLAG-syntaxin 18 mutant inhibited protein export from the endoplasmic reticulum. These results taken together suggest that syntaxin 18 functions in transport between the endoplasmic reticulum and Golgi.
Hatsuzawa
K
K
School of Life Science, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo 192-0392, Japan.
Hirose
H
H
Tani
K
K
Yamamoto
A
A
Scheller
R H
RH
Tagaya
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001692:Biological Transport; D003594:Cytoplasmic Granules / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008099:Liver / Q000378:metabolism / Q000648:ultrastructure; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism; D050765:Qa-SNARE Proteins; D051381:Rats; D017208:Rats, Wistar; D050600:SNARE Proteins; D016415:Sequence Alignment; D033921:Vesicular Transport Proteins
D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins