Open AccessAlternative splicing directs dual localization of C andida albicans 6‐phosphogluconate dehydrogenase to cytosol and peroxisomes
Author(s) -
Strijbis Karin,
den Burg Janny,
F. Visser Wouter,
den Berg Marlene,
Distel Ben
Publication year - 2012
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2011.00761.x
Subject(s) - peroxisome , biology , biochemistry , peroxisomal targeting signal , dehydrogenase , cytosol , idh1 , pentose phosphate pathway , enzyme , gene , mutation , glycolysis
The pentose phosphate pathway ( PPP ) is the main source of NADPH in the cell and therefore essential for the maintenance of the redox balance and anabolic reactions. NADPH is produced by the two dehydrogenases in the oxidative branch of the PPP : glucose‐6‐phosphate dehydrogenase ( Z wf1) and 6‐phosphogluconate dehydrogenase ( G nd1). We observed that in the commensal fungus C andida albicans these two enzymes contain putative peroxisomal targeting signals ( PTS s): Z wf1 has a putative PTS 1, while the annotated intron of GND1 encodes a PTS 2. By subcellular fractionation and fluorescence microscopy, we show that both enzymes have a dual localization in which the majority is cytosolic, but a small fraction is peroxisome associated. Analysis of GND1 transcripts revealed that dual targeting of G nd1 is directed by alternative splicing resulting in two G nd1 isoforms, one without targeting signals localized to the cytosol and one with an N ‐terminal PTS 2 targeted to peroxisomes. To our knowledge, G nd1 is the first example of dual targeting of a protein by alternative splicing in C . albicans . In silico analysis suggests that PTS ‐mediated peroxisomal targeting of Z wf1 and G nd1 is conserved across closely related C andida species. We discuss putative functions of the peroxisomal oxidative PPP in these organisms.