High impact information on SIT1

• Deletion of ARN3 did not prevent yeast from using ferrioxamine B as an iron source; however, deletion of ARN3 and FET3, a component of the high affinity ferrous iron transport system, did prevent uptake of ferrioxamine-bound iron and growth on ferrioxamine as an iron source [1].
• One of these, Arn3p/Sit1p, facilitates the uptake of ferrioxamine B, a siderophore of the hydroxamate class [2].
• A mutation of FTR1 did not impair the use of these siderophores but did affect the uptake of ferrioxamines E and B, as well as of ferric citrate, indicating that their utilization was independent of Sit1p [3].
• The human fungal pathogen Candida albicans contains a close homologue of yeast siderophore transporters, designated Sit1p/Arn1p [3].
• Heterologous expression of SIT1 in the yeast Saccharomyces cerevisiae confirmed the function of Sit1p as a transporter for ferrichrome-type siderophores [3].

Biological context of SIT1

• From yeast genome sequencing data six genes of the unknown major facilitator (UMF) family were known of which YEL065w Sce was recently identified as a transporter for the bacterial siderophore ferrioxamine B (Sit1p) [4].

Anatomical context of SIT1

• The sit1 mutant was defective in infection of a reconstituted human epithelium as a model for human oral mucosa, while the SIT1 strain was invasive [3].

Associations of SIT1 with chemical compounds

• Genes encoding transporters for heterologous siderophores have been identified in Saccharomyces cerevisiae, of which SIT1, TAF1, and ENB1 encode the transporters for ferrioxamines, ferric triacetylfusarinine C and ferric enterobactin, respectively [5].

Other interactions of SIT1

• 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 [3].
• For these experiments, we utilized yeast lacking the major iron uptake pathways (FET3 and FET4) and yeast deficient in SIT1, encoding the major up-regulated iron siderophore transporter [6].

References