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- Title
Aspergillus nidulans CkiA is an essential casein kinase I required for delivery of amino acid transporters to the plasma membrane.
- Authors
Apostolaki, Angeliki; Harispe, Laura; Calcagno-Pizarelli, Ana María; Vangelatos, Ioannis; Sophianopoulou, Vicky; Arst Jr, Herbert N.; Peñalva, Miguel Angel; Amillis, Sotiris; Scazzocchio, Claudio
- Abstract
Type I casein kinases are highly conserved among Eukaryotes. Of the two Aspergillus nidulans casein kinases I, CkiA is related to the δ/ε mammalian kinases and to Saccharomyces cerevisiæ Hrr25p. CkiA is essential. Three recessive ckiA mutations leading to single residue substitutions, and downregulation using a repressible promoter, result in partial loss-of-function, which leads to a pleiotropic defect in amino acid utilization and resistance to toxic amino acid analogues. These phenotypes correlate with miss-routing of the YAT plasma membrane transporters AgtA (glutamate) and PrnB (proline) to the vacuole under conditions that, in the wild type, result in their delivery to the plasma membrane. Miss-routing to the vacuole and subsequent transporter degradation results in a major deficiency in the uptake of the corresponding amino acids that underlies the inability of the mutant strains to catabolize them. Our findings may have important implications for understanding how CkiA, Hrr25p and other fungal orthologues regulate the directionality of transport at the ER-Golgi interface.
- Subjects
CASEIN kinase; EUKARYOTES; ASPERGILLUS nidulans; SACCHAROMYCES cerevisiae; CELL membranes; AMINO acid transport
- Publication
Molecular Microbiology, 2012, Vol 84, Issue 3, p530
- ISSN
0950-382X
- Publication type
Article
- DOI
10.1111/j.1365-2958.2012.08042.x