High impact information on ARN1

• A receptor domain controls the intracellular sorting of the ferrichrome transporter, ARN1 [1].
• At higher concentrations of ferrichrome, Arn1p cycles between the plasma membrane and endosome [1].
• Arn1p contains two binding sites for ferrichrome: one site has an affinity similar to the K(T) for transport, but the second site has a much higher affinity [1].
• Mutation of phenylalanine residues in the cytosolic tail of Arn1p also lead to missorting, but without defects in ferrichrome binding [1].
• At higher concentrations of ferrichrome, Arn1p relocalizes to the plasma membrane and rapidly undergoes endocytosis [2].

Biological context of ARN1

• Identification and substrate specificity of a ferrichrome-type siderophore transporter (Arn1p) in Saccharomyces cerevisiae [3].
• QTG mapped regulator-target pairs linked to ARN1 were combined to form a regulatory module, which we observed to be highly enriched in iron homeostasis related genes and contained several causally directed links that had not been identified in other automatic reconstructions of that regulatory module [4].
• FIT-deletion strains exhibited increased expression of Aft1p target genes as measured by a FET3-lacZ reporter gene or by Arn1p Western blotting, indicating that cells respond to the absence of FIT genes by up-regulating systems of iron uptake [5].

Anatomical context of ARN1

• Epitope-tagged Arn1p was expressed in intracellular vesicles in a pattern that was indistinguishable from that of Arn3p, whereas Ftr1p, a component of the high-affinity ferrous system, was expressed on the plasma membrane [6].

Associations of ARN1 with chemical compounds

• Ferrichromes possessing short-chain ornithine-N(delta)-acetyl residues such as ferrichrome, ferricrocin and ferrichrysin, were excluded by the Arn1 transporter [3].
• Arn1 was preferentially modified with polyubiquitin chains on a cluster of lysine residues at the amino terminus of the transporter [7].

Other interactions of ARN1

• These results suggest that siderophore uptake by Sit1p/Arn1p is required in a specific process of C. albicans infection, namely epithelial invasion and penetration, while in the blood or within organs other sources of iron, including heme, may be used [8].
• A family of four putative transporters (Arn1p-4p) in Saccharomyces cerevisiae is expressed under conditions of iron deprivation and is regulated by Aft1p, the major iron-dependent transcription factor in yeast [6].
• Uptake of triacetylfusarinine C was facilitated by Arn2p, although small amounts of uptake also occurred through Arn1p and Arn3p [6].

References