Overexpression of Rab22a hampers the transport between endosomes and the Golgi apparatus

Journal Article · Fri Apr 01 04:00:00 EST 2005 · Experimental Cell Research

DOI:https://doi.org/10.1016/j.yexcr.2004.11.017· OSTI ID:20717561

Mesa, Rosana ^[1]; Magadan, Javier ^[1]; Barbieri, Alejandro ^[2]; Lopez, Cecilia ^[1]; Stahl, Philip D ^[2]; Mayorga, Luis S ^[1]

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1. Laboratorio de Biologia Celular y Molecular, Instituto de Histologia y Embriologia (IHEM-CONICET), Facultad de Ciencias Medicas, Universidad Nacional de Cuyo, 5500 Mendoza (Argentina)
2. Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States)

The transport and sorting of soluble and membrane-associated macromolecules arriving at endosomal compartments require a complex set of Rab proteins. Rab22a has been localized to the endocytic compartment; however, very little is known about the function of Rab22a and inconsistent results have been reported in studies performed in different cell lines. To characterize the function of Rab22a in endocytic transport, the wild-type protein (Rab22a WT), a hydrolysis-deficient mutant (Rab22a Q64L), and a mutant with reduced affinity for GTP (Rab22a S19N) were expressed in CHO cells. None of the three Rab22a constructs affected the transport of rhodamine-dextran to lysosomes, the digestion of internalized proteins, or the lysosomal localization of cathepsin D. In contrast with the mild effect of Rab22a on the endosome-lysosome route, cells expressing Rab22a WT and Rab22a Q64L presented a strong delay in the retrograde transport of cholera toxin from endosomes to the Golgi apparatus. Moreover, these cells accumulated the cation independent mannose 6-phosphate receptor in endosomes. These observations indicate that Rab22a can affect the trafficking from endosomes to the Golgi apparatus probably by promoting fusion among endosomes and impairing the proper segregation of membrane domains required for targeting to the trans-Golgi network (TGN)

• OSTI ID: 20717561
• Journal Information: Experimental Cell Research, Journal Name: Experimental Cell Research Journal Issue: 2 Vol. 304; ISSN 0014-4827; ISSN ECREAL
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
CATHEPSINS
CATIONS
CHO CELLS
CHOLERA
DEXTRAN
DIGESTION
GOLGI COMPLEXES
HYDROLYSIS
LYSOSOMES
MANNOSE
MUTANTS
RECEPTORS
TOXINS