Golgi localization and functionally important domains in the NH2 and COOH terminus of the yeast CLC putative chloride channel Gef1p

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Item Type:	Article
Title:	Golgi localization and functionally important domains in the NH2 and COOH terminus of the yeast CLC putative chloride channel Gef1p
Creators Name:	Schwappach, B., Stobrawa, S., Hechenberger, M., Steinmeyer, K. and Jentsch, T.J.
Abstract:	GEF1 encodes the single CLC putative chloride channel in yeast. Its disruption leads to a defect in iron metabolism (Greene, J. R., Brown, N. H., DiDomenico, B. J., Kaplan, J., and Eide, D. (1993) Mol. Gen. Genet. 241, 542-553). Since disruption of GEF2, a subunit of the vacuolar H+-ATPase, leads to a similar phenotype, it was previously suggested that the chloride conductance provided by Gef1p is necessary for vacuolar acidification. We now show that gef1 cells indeed grow less well at less acidic pH. However, no defect in vacuolar acidification is apparent from quinacrine staining, and Gef1p co-localizes with Mnt1p in the medial Golgi. Thus, Gef1p may be important in determining Golgi pH. Systematic alanine scanning of the amino and the carboxyl terminus revealed several regions essential for Gef1p localization and function. One sequence (FVTID) in the amino terminus conforms to a class of sorting signals containing aromatic amino acids. This was further supported by point mutations. Alanine scanning of the carboxyl terminus identified a stretch of roughly 25 amino acids which coincides with the second CBS domain, a conserved protein motif recently identified. Mutations in the first CBS domain also destroyed proper function and localization. The second CBS domain can be transplanted to the amino terminus without loss of function, but could not be replaced by the corresponding domain of the homologous mammalian channel ClC-2.
Keywords:	Amino Acid Sequence, Biological Markers, Biological Transport, Chloride Channels, Fungal Proteins, Golgi Apparatus, Hydrogen-Ion Concentration, Immunohistochemistry, Iron, Mannosyltransferases, Membrane Proteins, Molecular Sequence Data, Mutagenesis, Peptides, Proprotein Convertases, Quinacrine, Saccharomyces Cerevisiae, Saccharomyces Cerevisiae Proteins, Sequence Alignment, Sequence Deletion, Subtilisins
Source:	Journal of Biological Chemistry
ISSN:	0021-9258
Publisher:	American Society for Biochemistry and Molecular Biology
Volume:	273
Number:	24
Page Range:	15110-15108
Date:	12 June 1998
Official Publication:	https://doi.org/10.1074/jbc.273.24.15110
PubMed:	View item in PubMed

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