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Transport route for synaptobrevin via a novel pathway of insertion into the endoplasmic reticulum membrane.
Author(s) -
Kutay U.,
AhnertHilger G.,
Hartmann E.,
Wiedenmann B.,
Rapoport T.A.
Publication year - 1995
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1995.tb06994.x
Subject(s) - synaptobrevin , endoplasmic reticulum , biology , snap25 , microbiology and biotechnology , membrane protein , golgi apparatus , protein targeting , vesicle , vesicle associated membrane protein 8 , snap23 , transport protein , biochemistry , synaptic vesicle , membrane
Synaptobrevin/vesicle‐associated membrane protein is one of the soluble N‐ethylmaleimide‐sensitive factor attachment protein receptor (SNARE) proteins. It is proposed to provide specificity for the targeting and fusion of vesicles with the plasma membrane. It belongs to a class of membrane proteins which lack a signal sequence and contain a single hydrophobic segment close to their C‐terminus, leaving most of the polypeptide chain in the cytoplasm (tail‐anchored). We show that in neuroendocrine PC12 cells, synaptobrevin is not directly incorporated into the target organelle, synaptic‐like vesicles. Rather, it is first inserted into the endoplasmic reticulum (ER) membrane and is then transported via the Golgi apparatus. Its insertion into the ER membrane in vitro occurs post‐translationally, is dependent on ATP and results in a trans‐membrane orientation of the hydrophobic tail. Membrane integration requires ER protein(s) different from the translocation components needed for proteins with signal sequences, thus suggesting a novel mechanism of insertion.