ERS1/YCR075C Summary Help

Standard Name ERS1 1
Systematic Name YCR075C
Feature Type ORF, Verified
Description Protein with similarity to human cystinosin; cystinosin is a H(+)-driven transporter involved in L-cystine export from lysosomes and implicated in the disease cystinosis; contains seven transmembrane domains (1, 2 and see Summary Paragraph)
Name Description ERd Suppressor 1
Chromosomal Location
ChrIII:248815 to 248033 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All ERS1 GO evidence and references
  View Computational GO annotations for ERS1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 3 genes
Classical genetics
Large-scale survey
75 total interaction(s) for 57 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 2
  • Affinity Capture-RNA: 2
  • Biochemical Activity: 1
  • PCA: 5
  • Reconstituted Complex: 2

Genetic Interactions
  • Dosage Rescue: 1
  • Negative Genetic: 56
  • Positive Genetic: 6

Expression Summary
Length (a.a.) 260
Molecular Weight (Da) 30,116
Isoelectric Point (pI) 8.93
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrIII:248815 to 248033 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2011-02-03 | Sequence: 1997-01-28
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..783 248815..248033 2011-02-03 1997-01-28
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | TCDB | UniProtKB
Primary SGDIDS000000671

ERS1 encodes an endosomal and vacuolar-localized seven transmembrane domain-containing cystine transporter (1, 3). Cystine, the disulfide-linked form of cysteine, is generated as a byproduct of protein hydrolysis in the vacuole, and must be exported to the cytoplasm where it is reduced to cysteine. ERS1 was originally isolated as a suppressor of an ERD1 mutation (1). ERD1 mutants are defective in the HDEL tetrapeptide-mediated retrieval and retention of lumenal endoplasmic reticulum (ER) proteins, and are also defective in Golgi-dependent glycoprotein processing (4). ERS1 deletion mutants are viable and display hygromycin B sensitivity but are not defective in the retention of ER proteins (1, 3). MEH1, a gene involved in vacuolar acidification and positive regulation of microautophagy, has been identified as a high-copy number suppressor of an ERS1 deletion (3).

Cystinosin, a lysosomal H(+)-driven cystine transporter encoded by the CTNS (OMIM) locus in humans is a functional homolog of Ers1p (3, 2). The human cystinosin symporter is responsible for the export of cystine from lysosomes (2). Mutations in the CTNS gene result in several related cystinotic disorders including nephropathic cystinosis, a lysosomal storage disease characterized by the accumulation of cystine crystals in various organs including the eyes, kidneys, and liver (5). This disorder presents clinically as renal Fanconi Syndrome (OMIM), a failure of the kidneys to reabsorb nutrients and minerals that results in end-stage kidney failure (5). A strong correlation exists between the clinical severity associated with various CTNS mutant alleles identified in cystinosis patients and the degree with which these mutant alleles are able to complement an ERS1 deletion strain (3).

Last updated: 2007-02-14 Contact SGD

References cited on this page View Complete Literature Guide for ERS1
1) Hardwick KG and Pelham HR  (1990) ERS1 a seven transmembrane domain protein from Saccharomyces cerevisiae. Nucleic Acids Res 18(8):2177
2) Kalatzis V, et al.  (2001) Cystinosin, the protein defective in cystinosis, is a H(+)-driven lysosomal cystine transporter. EMBO J 20(21):5940-9
3) Gao XD, et al.  (2005) ERS1 encodes a functional homologue of the human lysosomal cystine transporter. FEBS J 272(10):2497-511
4) Hardwick KG, et al.  (1990) ERD1, a yeast gene required for the retention of luminal endoplasmic reticulum proteins, affects glycoprotein processing in the Golgi apparatus. EMBO J 9(3):623-30
5) Town M, et al.  (1998) A novel gene encoding an integral membrane protein is mutated in nephropathic cystinosis. Nat Genet 18(4):319-24