Scientific article
Open access

Involvement of the transmembrane protein p23 in biosynthetic protein transport

Published inThe Journal of cell biology, vol. 139, no. 5, p. 1119-1135
Publication date1997

Here, we report the localization and characterization of BHKp23, a member of the p24 family of transmembrane proteins, in mammalian cells. We find that p23 is a major component of tubulovesicular membranes at the cis side of the Golgi complex (estimated density: 12,500 copies/μm2 membrane surface area, or ≈30% of the total protein). Our data indicate that BHKp23-containing membranes are part of the cis-Golgi network/intermediate compartment. Using the G protein of vesicular stomatitis virus as a transmembrane cargo molecule, we find that p23 membranes are an obligatory station in forward biosynthetic membrane transport, but that p23 itself is absent from transport vesicles that carry the G protein to and beyond the Golgi complex. Our data show that p23 is not present to any significant extent in coat protein (COP) I-coated vesicles generated in vitro and does not colocalize with COP I buds and vesicles. Moreover, we find that p23 cytoplasmic domain is not involved in COP I membrane recruitment. Our data demonstrate that microinjected antibodies against the cytoplasmic tail of p23 inhibit G protein transport from the cis- Golgi network/intermediate compartment to the cell surface, suggesting that p23 function is required for the transport of transmembrane cargo molecules. These observations together with the fact that p23 is a highly abundant component in the intermediate compartment, lead us to propose that p23 contributes to membrane structure, and this contribution is necessary for efficient segregation and transport.

Citation (ISO format)
ROJO ORTIZ DE LANZAGORTA, Manuel et al. Involvement of the transmembrane protein p23 in biosynthetic protein transport. In: The Journal of cell biology, 1997, vol. 139, n° 5, p. 1119–1135. doi: 10.1083/jcb.139.5.1119
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Article (Published version)
ISSN of the journal0021-9525

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