Τίτλος:
Functional characterization of NAT/NCS2 proteins of Aspergillus brasiliensis reveals a genuine xanthine-uric acid transporter and an intrinsically misfolded polypeptide
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
The Nucleobase-Ascorbate Transporter (NAT) family includes members in nearly all domains of life. Functionally characterized NAT transporters from bacteria, fungi, plants and mammals are ion-coupled symporters specific for the uptake of purines, pyrimidines and related analogues. The characterized mammalian NATs are specific for the uptake of L-ascorbic acid. In this work we identify in silico a group of fungal putative transporters, named UapD-like proteins, which represent a novel NAT subfamily. To understand the function and specificity of UapD proteins, we cloned and functionally characterized the two Aspergillus brasiliensis NAT members (named AbUapC and AbUapD) by heterologous expression in Aspergillus nidulans. AbUapC represents canonical NATs (UapC or UapA), while AbUapD represents the new subfamily. AbUapC is a high-affinity, high-capacity, H+/xanthine-uric acid transporter, which can also recognize other purines with very low affinity. No apparent transport function could be detected for AbUapD. GFP-tagging showed that, unlike AbUapC which is localized in the plasma membrane, AbUapD is ER-retained and degraded in the vacuoles, a characteristic of misfolded proteins. Chimeric UapA/AbUapD molecules are also turned-over in the vacuole, suggesting that UapD includes intrinsic peptidic sequences leading to misfolding. The possible evolutionary implication of such conserved, but inactive proteins is discussed. © 2015.
Συγγραφείς:
Krypotou, E.
Scazzocchio, C.
Diallinas, G.
Περιοδικό:
Fungal Genetics and Biology
Εκδότης:
Academic Press Inc.
Λέξεις-κλειδιά:
nucleobase ascorbate transporter; nucleobase transporter; unclassified drug; urate transporter; xanthine; fungal protein; hybrid protein; nucleobase transporter; peptide; uric acid; xanthine derivative, amino acid sequence; Article; Aspergillus; Aspergillus brasiliensis; binding affinity; binding site; cell membrane; controlled study; endoplasmic reticulum; fungal gene; nonhuman; phylogeny; protein binding; protein expression; protein family; protein folding; protein function; protein localization; protein misfolded; protein transport; pseudogene; UapD gene; Aspergillus; Aspergillus nidulans; chemistry; computer simulation; genetics; metabolism; molecular genetics; protein folding; sequence alignment; synthesis; transport at the cellular level, Aspergillus brasiliensis; Emericella nidulans; Fungi; Mammalia, Amino Acid Sequence; Amino Acid Sequence; Aspergillus; Aspergillus; Aspergillus nidulans; Aspergillus nidulans; Biological Transport; Biological Transport; Computer Simulation; Computer Simulation; Fungal Proteins; Fungal Proteins; Molecular Sequence Data; Molecular Sequence Data; Nucleobase Transport Proteins; Nucleobase Transport Proteins; Peptides; Peptides; Phylogeny; Phylogeny; Protein Folding; Protein Folding; Recombinant Fusion Proteins; Recombinant Fusion Proteins; Sequence Alignment; Sequence Alignment; Uric Acid; Uric Acid; Xanthines; Xanthines
DOI:
10.1016/j.fgb.2015.01.009
