AUTHOR=Kremp Marco , Bittner Elena , Martorana Domenica , Klingenberger Alexander , Stehlik Thorsten , Bölker Michael , Freitag Johannes 

TITLE=Non-AUG Translation Initiation Generates Peroxisomal Isoforms of 6-Phosphogluconate Dehydrogenase in Fungi

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2020.00251

DOI=10.3389/fcell.2020.00251

ISSN=2296-634X

ABSTRACT=<p>Proteins destined for transport to specific organelles usually contain targeting information, which are embedded in their sequence. Many enzymes are required in more than one cellular compartment and different molecular mechanisms are used to achieve dual localization. Here we report a cryptic type 2 peroxisomal targeting signal encoded in the 5′ untranslated region of fungal genes coding for 6-phosphogluconate dehydrogenase (PGD), a key enzyme of the oxidative pentose phosphate pathway. The conservation of the cryptic PTS2 motif suggests a biological function. We observed that translation from a non-AUG start codon generates an N-terminally extended peroxisomal isoform of <italic>Ustilago maydis</italic> PGD. Non-canonical initiation occurred at the sequence AGG AUU, consisting of two near-cognate start codons in tandem. Taken together, our data reveal non-AUG translation initiation as an additional mechanism to achieve the dual localization of a protein required both in the cytosol and the peroxisomes.</p>