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SLC45A2 (solute carrier family 45 member 2)

Written2019-01Mainak Sengupta, Tithi Dutta, Kunal Ray
University of Calcutta, Department of Genetics, 35, Ballygunge Circular Road, Kolkata - 700 019, India.; (MS, TD) ATGC Diagnostics Private Limited, Kolkata, India, (KR)

Abstract SLC45A2 gene, having a chromosomal location 5p13.2, encodes a membrane associated transporter protein (MATP). MATP is a transmembrane protein. It is present in the melanosomal membrane in the melanocytes. It maintains the osmotic potential by regulating the pH of the melanosomal lumen. Defects in the SLC45A2 gene causes oculocutaneous albinism type IV; OCA IV

Keywords SLC45A2, MATP, albinism, OCA IV

(Note : for Links provided by Atlas : click)


Alias (NCBI)Membrane Associated Transporter Protein
Melanoma Antigen AIM1
AIM1 (absent in melanoma 1)
HGNC (Hugo) SLC45A2
HGNC Alias symbAIM-1
HGNC Previous nameMATP
HGNC Previous namemembrane associated transporter
 solute carrier family 45, member 2
LocusID (NCBI) 51151
Atlas_Id 41306
Location 5p13.2  [Link to chromosome band 5p13]
Location_base_pair Starts at 33944623 and ends at 33984693 bp from pter ( according to GRCh38/hg38-Dec_2013)  [Mapping SLC45A2.png]
  SLC45A2 Gene in genomic location: Cytogenetic band: 5p13.2 by Entrez Gene, 5p13.2 by HGNC, 5p13.2. The figure represents the cytogenetic banding of SLC45A2 locus (Ref
Fusion genes
(updated 2017)
Data from Atlas, Mitelman, Cosmic Fusion, Fusion Cancer, TCGA fusion databases with official HUGO symbols (see references in chromosomal bands)


Description In Chromosome 5, the 40,529 bases of DNA starts from 33,944,616 and ends at 33,985,144(GRCh38/hg38). Orientation: Minus strand. It contains 7 exons.
Transcription The gene after transcription produces 7 different mRNAs, 6 alternatively spliced variants and 1 unspliced form. There are 4 non overlapping alternative last exons (


Description The human SLC45A2 protein is a 530-amino acid polypeptide that contains 12 putative trans-membrane domains, and is only expressed in the melanosomes in the melanocytes (Newton et al., 2001). The SLC45A2 gene initially identified as AIM1 (absent in melanoma 1) by Newton et al, 2001 encodes a Membrane-Associated Transporter Protein (MATP). It acts as a transporter and regulates the melanosomal pH using a proton gradient.
Expression The MATP protein (58 kDa) is expressed in most melanoma cell lines and melanocytes and sorted into the melanosomal membrane. The highest expression level has been observed in the pigmented layer of retina (
Localisation It is a transmembrane protein present in the melanosomal membrane in melanin producing melanocytes.
Function SLC45A2 (MATP) allows the transport of sugar molecule across the membrane into the cytoplasm and maintains osmotic potential of the melanosomes (Rabea Bartolke, 2014, Reinders et al 2015). It maintains the pH of the melanosome which facilitates the binding of Copper to Tyrosinase resulting in the conversion of Apo-Tyrosinase to Tyrosinase. (Newton et al, 2011).
  The SLC45A2 (MATP) acts as a transporter present on the melanosomal membrane. Under normal condition it controls the pH by using a proton gradient. Thus helps in Copper to bind to Apo-Tyrosinase and convert it to active Tyrosinase. In oculocutaneous albinism type IV (OCA4), any deleterious mutation in melanosomal MATP transporter protein makes the melanosomal lumen acidic. Under this condition, the Cu fails to bind to the Apo-Tyr and Tyrosinase activity is reduced. (Bin et al, 2015).
Homology The human MATP shows syntenic homology with the proximal region of mouse chromosome 15. The human orthologue for the mouse underwhite gene locus (uw gene) is encoded by SLC45A2 gene. The predicted mouse MATP protein is 82% identical and 87% similar to the human MATP protein.
The highest degree of homology was found between MATP and sucrose/proton symporters found in plants. The homologous region of MATP includes the sucrose-transporter signature sequence: R-X-G-R-[K/R], found in between the transmembrane domains 2 and 3 (Meyer H et al, 2011, Newton et al, 2011).
The sucrose transporter Slc45-1 in Drosophila shows significant similarity to mammalian SLC45A2 and plays a role in melanin synthesis.


Epigenetics In an attempt to identify genetic and epigenetic marks involved in population structure, a coding SNP: rs16891982 (p.L374F) of SLC45A2, known to play a role in normal pigmentation variation, was found to positively correlate with the methylation level of PM20D1 gene. The minor allele A was been found to be associated with lower methylation of the target gene. (
Germinal Homozygous mutation or Compound Heterozygote mutations in SLC45A2 gene has been found responsible for causing Oculocutaneous Albinism Type 4 (OCA4). To date around 80 mutations have been reported in SLC45A2 responsible for OCA4. (Kamaraj et al. 2014, Toth et al. 2017). OCA4 was first observed in Turkish population, it is rare among Caucasians and Africans and in Japan it is diagnosed in one of four persons affected with OCA.

There are several non-pathogenic polymorphisms which result into mild pigmentation.

The haplotypes at SLC45A2 is significantly associated in determination of dark or light pigmentation features in human population. (Fracasso et al.2017)

Implicated in

Entity Oculocutaneous albinism type IV (OCA IV)
Disease OCA IV is an autosomal recessive disorder of melanin biosynthesis that results in congenital hypopigmentation of ocular and cutaneous tissues. Common developmental abnormalities of the eye like decreased visual acuity, macular hypoplasia, optic dysplasia, atypical choroidal vessels, and nystagmus are observed in patient suffering from OCA type IV. The severity of hypopigmentation is correlated with melanosome size, shape, melanin content and maturity of the melanosomal structures demonstrating that the encoded protein is a major determinant of mammalian pigmentation.
Entity Melanoma
Note n 2017, Park et al reported that a few variants present in SLC45A2 gene can be a promising immune therapeutic target for melanoma with high tumor selectivity and reduced potential for autoimmune toxicity. It is associated with an increased risk for melanoma in light-skinned populations, and the encoded protein can elicit immune recognition. The Cancer Genome Atlas Research Network (TCGA) database reported that it is expressed by approximately 80% of cutaneous melanomas. In the same year Hafner et al showed that SLC45A2 (also called AIM1, absent in melanoma 1) function as a key suppressor of invasive phenotypes by working in association with the actin cytoskeleton. SLC45A2 becomes dysregulated and suppresses cytoskeletal remodelling in primary and metastatic prostate cancer and in non-malignant prostate epithelial cells. In 2012, Fernandez et al reported in a family that adult siblings presented with congenital neutropenia which later developed into Crohn's Disease. Molecular characterisation revealed homozygous mutations both in G6PC3 and SLC45A2 in the sister and mutation in single allele for both genes in the brother.


Proton-associated sucrose transport of mammalian solute carrier family 45: an analysis in Saccharomyces cerevisiae
Bartölke R, Heinisch JJ, Wieczorek H, Vitavska O
Biochem J 2014 Dec 1;464(2):193-201
PMID 25164149
Membrane-Associated Transporter Protein (MATP) Regulates Melanosomal pH and Influences Tyrosinase Activity
Bin BH, Bhin J, Yang SH, Shin M, Nam YJ, Choi DH, Shin DW, Lee AY, Hwang D, Cho EG, Lee TR
PLoS One 2015 Jun 9;10(6):e0129273
PMID 26057890
Mutational analysis of oculocutaneous albinism: a compact review
Kamaraj B, Purohit R
Biomed Res Int 2014;2014:905472
PMID 25093188
SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans
Lamason RL, Mohideen MA, Mest JR, Wong AC, Norton HL, Aros MC, Jurynec MJ, Mao X, Humphreville VR, Humbert JE, Sinha S, Moore JL, Jagadeeswaran P, Zhao W, Ning G, Makalowska I, McKeigue PM, O'donnell D, Kittles R, Parra EJ, Mangini NJ, Grunwald DJ, Shriver MD, Canfield VA, Cheng KC
Science 2005 Dec 16;310(5755):1782-6
PMID 16357253
Identification of an animal sucrose transporter
Meyer H, Vitavska O, Wieczorek H
J Cell Sci 2011 Jun 15;124(Pt 12):1984-91
PMID 21586609
Mutations in the human orthologue of the mouse underwhite gene (uw) underlie a new form of oculocutaneous albinism, OCA4
Newton JM, Cohen-Barak O, Hagiwara N, Gardner JM, Davisson MT, King RA, Brilliant MH
Am J Hum Genet 2001 Nov;69(5):981-8
PMID 11574907
Investigating polymorphisms in membrane-associated transporter protein SLC45A2, using sucrose transporters as a model
Reinders A, Ward JM
Mol Med Rep 2015 Jul;12(1):1393-8
PMID 25760657
Identification of two novel mutations in the SLC45A2 gene in a Hungarian pedigree affected by unusual OCA type 4
Tóth L, Fábos B, Farkas K, Sulák A, Tripolszki K, Széll M, Nagy N
BMC Med Genet 2017 Mar 15;18(1):27
PMID 28298193


This paper should be referenced as such :
Mainak Sengupta, Tithi Dutta, Kunal Ray
SLC45A2 (solute carrier family 45 member 2)
Atlas Genet Cytogenet Oncol Haematol. 2019;23(7):187-189.
Free journal version : [ pdf ]   [ DOI ]

Other Cancer prone implicated (Data extracted from papers in the Atlas) [ 1 ]
  Oculocutaneous Albinism

External links


HGNC (Hugo)SLC45A2   16472
Atlas Explorer : (Salamanque)SLC45A2
Entrez_Gene (NCBI)SLC45A2    solute carrier family 45 member 2
Aliases1A1; AIM1; MATP; OCA4; 
GeneCards (Weizmann)SLC45A2
Ensembl hg19 (Hinxton)ENSG00000164175 [Gene_View]
Ensembl hg38 (Hinxton)ENSG00000164175 [Gene_View]  ENSG00000164175 [Sequence]  chr5:33944623-33984693 [Contig_View]  SLC45A2 [Vega]
ICGC DataPortalENSG00000164175
TCGA cBioPortalSLC45A2
AceView (NCBI)SLC45A2
Genatlas (Paris)SLC45A2
SOURCE (Princeton)SLC45A2
Genetics Home Reference (NIH)SLC45A2
Genomic and cartography
GoldenPath hg38 (UCSC)SLC45A2  -     chr5:33944623-33984693 -  5p13.2   [Description]    (hg38-Dec_2013)
GoldenPath hg19 (UCSC)SLC45A2  -     5p13.2   [Description]    (hg19-Feb_2009)
GoldenPathSLC45A2 - 5p13.2 [CytoView hg19]  SLC45A2 - 5p13.2 [CytoView hg38]
Genome Data Viewer NCBISLC45A2 [Mapview hg19]  
OMIM227240   606202   606574   
Gene and transcription
Genbank (Entrez)AF172849 BC003597 BC064405 BQ677785 BU166522
RefSeq transcript (Entrez)NM_001012509 NM_001297417 NM_016180
Consensus coding sequences : CCDS (NCBI)SLC45A2
Gene ExpressionSLC45A2 [ NCBI-GEO ]   SLC45A2 [ EBI - ARRAY_EXPRESS ]   SLC45A2 [ SEEK ]   SLC45A2 [ MEM ]
Gene Expression Viewer (FireBrowse)SLC45A2 [ Firebrowse - Broad ]
GenevisibleExpression of SLC45A2 in : [tissues]  [cell-lines]  [cancer]  [perturbations]  
BioGPS (Tissue expression)51151
GTEX Portal (Tissue expression)SLC45A2
Human Protein AtlasENSG00000164175-SLC45A2 [pathology]   [cell]   [tissue]
Protein : pattern, domain, 3D structure
UniProt/SwissProtQ9UMX9   [function]  [subcellular_location]  [family_and_domains]  [pathology_and_biotech]  [ptm_processing]  [expression]  [interaction]
NextProtQ9UMX9  [Sequence]  [Exons]  [Medical]  [Publications]
With graphics : InterProQ9UMX9
Domains : Interpro (EBI)MFS_trans_sf   
Domain families : Pfam (Sanger)
Domain families : Pfam (NCBI)
Conserved Domain (NCBI)SLC45A2
AlphaFold pdb e-kbQ9UMX9   
Human Protein Atlas [tissue]ENSG00000164175-SLC45A2 [tissue]
Protein Interaction databases
IntAct (EBI)Q9UMX9
Ontologies - Pathways
Ontology : AmiGOvisual perception  sucrose:proton symporter activity  sucrose:proton symporter activity  sucrose transport  membrane  integral component of membrane  melanosome membrane  melanin biosynthetic process  developmental pigmentation  response to stimulus  
Ontology : EGO-EBIvisual perception  sucrose:proton symporter activity  sucrose:proton symporter activity  sucrose transport  membrane  integral component of membrane  melanosome membrane  melanin biosynthetic process  developmental pigmentation  response to stimulus  
REACTOMEQ9UMX9 [protein]
REACTOME PathwaysR-HSA-5662702 [pathway]   
NDEx NetworkSLC45A2
Atlas of Cancer Signalling NetworkSLC45A2
Wikipedia pathwaysSLC45A2
Orthology - Evolution
GeneTree (enSembl)ENSG00000164175
Phylogenetic Trees/Animal Genes : TreeFamSLC45A2
Homologs : HomoloGeneSLC45A2
Homology/Alignments : Family Browser (UCSC)SLC45A2
Gene fusions - Rearrangements
Fusion : MitelmanSLC45A2::AMACR [5p13.2/5p13.2]  
Fusion : QuiverSLC45A2
Polymorphisms : SNP and Copy number variants
NCBI Variation ViewerSLC45A2 [hg38]
dbSNP Single Nucleotide Polymorphism (NCBI)SLC45A2
Exome Variant ServerSLC45A2
GNOMAD BrowserENSG00000164175
Varsome BrowserSLC45A2
ACMGSLC45A2 variants
Genomic Variants (DGV)SLC45A2 [DGVbeta]
DECIPHERSLC45A2 [patients]   [syndromes]   [variants]   [genes]  
CONAN: Copy Number AnalysisSLC45A2 
ICGC Data PortalSLC45A2 
TCGA Data PortalSLC45A2 
Broad Tumor PortalSLC45A2
OASIS PortalSLC45A2 [ Somatic mutations - Copy number]
Somatic Mutations in Cancer : COSMICSLC45A2  [overview]  [genome browser]  [tissue]  [distribution]  
Somatic Mutations in Cancer : COSMIC3DSLC45A2
Mutations and Diseases : HGMDSLC45A2
LOVD (Leiden Open Variation Database)[gene] [transcripts] [variants]
DgiDB (Drug Gene Interaction Database)SLC45A2
DoCM (Curated mutations)SLC45A2
CIViC (Clinical Interpretations of Variants in Cancer)SLC45A2
Impact of mutations[PolyPhen2] [Provean] [Buck Institute : MutDB] [Mutation Assessor] [Mutanalyser]
OMIM227240    606202    606574   
Genetic Testing Registry SLC45A2
NextProtQ9UMX9 [Medical]
Target ValidationSLC45A2
Huge Navigator SLC45A2 [HugePedia]
Clinical trials, drugs, therapy
Protein Interactions : CTDSLC45A2
Pharm GKB GenePA134897756
Clinical trialSLC45A2
DataMed IndexSLC45A2
PubMed77 Pubmed reference(s) in Entrez
GeneRIFsGene References Into Functions (Entrez)
REVIEW articlesautomatic search in PubMed
Last year publicationsautomatic search in PubMed

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