Sequence and overexpression of GPP130/GIMPc : evidence for saturable pH-sensitive targeting of a type II early Golgi membrane protein

Linstedt, A. D. and Mehta, A. and Suhan, J. and Reggio, H. and Hauri, H. P.. (1997) Sequence and overexpression of GPP130/GIMPc : evidence for saturable pH-sensitive targeting of a type II early Golgi membrane protein. Molecular Biology of the Cell, 8 (6). pp. 1073-1087.

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Official URL: http://edoc.unibas.ch/dok/A5257778

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It is thought that residents of the Golgi stack are localized by a retention mechanism that prevents their forward progress. Nevertheless, some early Golgi proteins acquire late Golgi modifications. Herein, we describe GPP130 (Golgi phosphoprotein of 130 kDa), a 130-kDa phosphorylated and glycosylated integral membrane protein localized to the cis/medial Golgi. GPP130 appears to be the human counterpart of rat Golgi integral membrane protein, cis (GIMPc), a previously identified early Golgi antigen that acquires late Golgi carbohydrate modifications. The sequence of cDNAs encoding GPP130 indicate that it is a type II membrane protein with a predicted molecular weight of 81,880 and an unusually acidic lumenal domain. On the basis of the alignment with several rod-shaped proteins and the presence of multiple predicted coiled-coil regions, GPP130 may form a flexible rod in the Golgi lumen. In contrast to the behavior of previously studied type II Golgi proteins, overexpression of GPP130 led to a pronounced accumulation in endocytotic vesicles, and endogenous GPP130 reversibly redistributed to endocytotic vesicles after chloroquine treatment. Thus, localization of GPP130 to the early Golgi involves steps that are saturable and sensitive to lumenal pH, and GPP130 contains targeting information that specifies its return to the Golgi after chloroquine washout. Given that GIMPc acquires late Golgi modifications in untreated cells, it seems likely that GPP130/GIMPc continuously cycles between the early Golgi and distal compartments and that an unidentified retrieval mechanism is important for its targeting.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Pharmacology/Neurobiology (Hauri)
UniBasel Contributors:Hauri, Hans-Peter
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Society for Cell Biology
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:07 Nov 2017 08:12
Deposited On:22 Mar 2012 13:18

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