Limits...
Rer1p, a retrieval receptor for endoplasmic reticulum membrane proteins, is dynamically localized to the Golgi apparatus by coatomer.

Sato K, Sato M, Nakano A - J. Cell Biol. (2001)

Bottom Line: Either a lesion of coatomer or deletion of the COOH-terminal tail of Rer1p causes its mislocalization to the vacuole.The COOH-terminal Rer1p tail interacts in vitro with a coatomer complex containing alpha and gamma subunits.These findings not only give the proof that Rer1p is a novel type of retrieval receptor recognizing the TMD in the Golgi but also indicate that coatomer actively regulates the function and localization of Rer1p.

View Article: PubMed Central - PubMed

Affiliation: Molecular Membrane Biology Laboratory, RIKEN (The Institute of Physical and Chemical Research), Saitama 351-0198, Japan. satoken@postman.riken.go.jp

ABSTRACT
Rer1p, a yeast Golgi membrane protein, is required for the retrieval of a set of endoplasmic reticulum (ER) membrane proteins. We present the first evidence that Rer1p directly interacts with the transmembrane domain (TMD) of Sec12p which contains a retrieval signal. A green fluorescent protein (GFP) fusion of Rer1p rapidly cycles between the Golgi and the ER. Either a lesion of coatomer or deletion of the COOH-terminal tail of Rer1p causes its mislocalization to the vacuole. The COOH-terminal Rer1p tail interacts in vitro with a coatomer complex containing alpha and gamma subunits. These findings not only give the proof that Rer1p is a novel type of retrieval receptor recognizing the TMD in the Golgi but also indicate that coatomer actively regulates the function and localization of Rer1p.

Show MeSH
Dynamic behavior of GFP-Rer1p in sec mutants. (a) sec13-1 (panels A–D) and sec18-1 (panels E–F) cells expressing GFP-Rer1p were first observed at 20°C (panels A and E) by confocal fluorescence microscopy. The temperature of the microscope stage was then raised to and kept at 37°C for the indicated times (panels B–D and F). The same cells (panels A–F) are shown. (b) Reversibility of the relocalization of GFP-Rer1p to the ER in sec13-1 cells. sec13-1 cells expressing GFP-Rer1p were incubated at 37°C for 30 min (panel A) and then shifted to room temperature (RT) and observed for the indicated times (panels B–D). Bars, 5 μm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2198819&req=5

Figure 3: Dynamic behavior of GFP-Rer1p in sec mutants. (a) sec13-1 (panels A–D) and sec18-1 (panels E–F) cells expressing GFP-Rer1p were first observed at 20°C (panels A and E) by confocal fluorescence microscopy. The temperature of the microscope stage was then raised to and kept at 37°C for the indicated times (panels B–D and F). The same cells (panels A–F) are shown. (b) Reversibility of the relocalization of GFP-Rer1p to the ER in sec13-1 cells. sec13-1 cells expressing GFP-Rer1p were incubated at 37°C for 30 min (panel A) and then shifted to room temperature (RT) and observed for the indicated times (panels B–D). Bars, 5 μm.

Mentions: If Rer1p is recycling between the Golgi and the ER, ER-to-Golgi anterograde transport would be required to ensure its steady-state localization in the Golgi. To test this possibility, GFP-Rer1p was expressed in the sec13 mutant cells which have a temperature-sensitive defect in the COPII vesicle formation from the ER (Kaiser and Schekman 1990). As shown in Fig. 3 a, GFP-Rer1p showed normal Golgi localization at 20°C (panel A), but when the temperature was shifted to 37°C, the fluorescence signal rapidly changed its pattern (panels B–D). The staining of the nuclear envelope and cell periphery seen at 37°C is a typical ER pattern of yeast. This relocalization is reversible. When the temperature is returned to the room temperature, GFP-Rer1p exhibits the Golgi pattern again (Fig. 3 b). Similar relocalization from the Golgi to the ER was also observed in sec16-2 (see Fig. 6 c) and sec23-1 cells at 37°C which are also defective in budding of the COPII vesicles from the ER.


Rer1p, a retrieval receptor for endoplasmic reticulum membrane proteins, is dynamically localized to the Golgi apparatus by coatomer.

Sato K, Sato M, Nakano A - J. Cell Biol. (2001)

Dynamic behavior of GFP-Rer1p in sec mutants. (a) sec13-1 (panels A–D) and sec18-1 (panels E–F) cells expressing GFP-Rer1p were first observed at 20°C (panels A and E) by confocal fluorescence microscopy. The temperature of the microscope stage was then raised to and kept at 37°C for the indicated times (panels B–D and F). The same cells (panels A–F) are shown. (b) Reversibility of the relocalization of GFP-Rer1p to the ER in sec13-1 cells. sec13-1 cells expressing GFP-Rer1p were incubated at 37°C for 30 min (panel A) and then shifted to room temperature (RT) and observed for the indicated times (panels B–D). Bars, 5 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2198819&req=5

Figure 3: Dynamic behavior of GFP-Rer1p in sec mutants. (a) sec13-1 (panels A–D) and sec18-1 (panels E–F) cells expressing GFP-Rer1p were first observed at 20°C (panels A and E) by confocal fluorescence microscopy. The temperature of the microscope stage was then raised to and kept at 37°C for the indicated times (panels B–D and F). The same cells (panels A–F) are shown. (b) Reversibility of the relocalization of GFP-Rer1p to the ER in sec13-1 cells. sec13-1 cells expressing GFP-Rer1p were incubated at 37°C for 30 min (panel A) and then shifted to room temperature (RT) and observed for the indicated times (panels B–D). Bars, 5 μm.
Mentions: If Rer1p is recycling between the Golgi and the ER, ER-to-Golgi anterograde transport would be required to ensure its steady-state localization in the Golgi. To test this possibility, GFP-Rer1p was expressed in the sec13 mutant cells which have a temperature-sensitive defect in the COPII vesicle formation from the ER (Kaiser and Schekman 1990). As shown in Fig. 3 a, GFP-Rer1p showed normal Golgi localization at 20°C (panel A), but when the temperature was shifted to 37°C, the fluorescence signal rapidly changed its pattern (panels B–D). The staining of the nuclear envelope and cell periphery seen at 37°C is a typical ER pattern of yeast. This relocalization is reversible. When the temperature is returned to the room temperature, GFP-Rer1p exhibits the Golgi pattern again (Fig. 3 b). Similar relocalization from the Golgi to the ER was also observed in sec16-2 (see Fig. 6 c) and sec23-1 cells at 37°C which are also defective in budding of the COPII vesicles from the ER.

Bottom Line: Either a lesion of coatomer or deletion of the COOH-terminal tail of Rer1p causes its mislocalization to the vacuole.The COOH-terminal Rer1p tail interacts in vitro with a coatomer complex containing alpha and gamma subunits.These findings not only give the proof that Rer1p is a novel type of retrieval receptor recognizing the TMD in the Golgi but also indicate that coatomer actively regulates the function and localization of Rer1p.

View Article: PubMed Central - PubMed

Affiliation: Molecular Membrane Biology Laboratory, RIKEN (The Institute of Physical and Chemical Research), Saitama 351-0198, Japan. satoken@postman.riken.go.jp

ABSTRACT
Rer1p, a yeast Golgi membrane protein, is required for the retrieval of a set of endoplasmic reticulum (ER) membrane proteins. We present the first evidence that Rer1p directly interacts with the transmembrane domain (TMD) of Sec12p which contains a retrieval signal. A green fluorescent protein (GFP) fusion of Rer1p rapidly cycles between the Golgi and the ER. Either a lesion of coatomer or deletion of the COOH-terminal tail of Rer1p causes its mislocalization to the vacuole. The COOH-terminal Rer1p tail interacts in vitro with a coatomer complex containing alpha and gamma subunits. These findings not only give the proof that Rer1p is a novel type of retrieval receptor recognizing the TMD in the Golgi but also indicate that coatomer actively regulates the function and localization of Rer1p.

Show MeSH