Human Transporter Database (HTD) is a comprehensive gene resource for human transporters. We also collect the information of the mouse and rat transporters for reference.

Transporters are often membrane proteins to control absorption, distribution, metabolism, and excretion of cellular metabolites, neurotransmitters, therapeutic drugs and environmental signals. As their indispensable roles in compound exchange and metabolic flux control, mutated transporters with diminished or absent functions are often related to metabolic disorders, neurological diseases, drug resistance, and side effects. Recently aberrant growth of high throughput data was produced for the gene expression, pharmacogenetic information, and drug interactions of human transporters. We manually checked and obtained transporter genes for human, mouse, and rat, respectively, collected their annotation information, and constructed the Human Transporter Database (HTD), hoping to facilitate related research.

We searched on NCBI-Gene database with several keywords, did BLAST, and manually checked each potential transmembrane transporter gene, to obtain a relatively confident, complete and recently-updated transporter gene list.

We established a classification for human transporters, to classify the transporter genes into ten major categories, such as 'ATP related', 'Channel', and 'Solute Carrier Family'. Users can browse the classification as well as TCDB, KEGG, GO classification systems for these genes on Classification page. The statistics for transporters within human, mouse and rat is shown below.

We also checked the distribution of human transporter genes, including their distribution on chromosomes, and the GO/pathway/disease enrichment analysis. The results could be seen on the Chromosome page and the Enrichment page (under Distribution on the menu).

We collected related annotation information mainly from public databases, including NCBI, UniProt, InterPro, Allen Brain Atlas, HapMap, DGV, KOBAS, PharmGKB, CTD, and DrugBank.

Below is the statistics for transporters in each species and class.
Category# transporter genes
ATP related 222 197 198
Aquaporin 19 13 13
Channel 427 397 442
Cytochrome c oxidase 75 54 63
Defensin 72 102 60
Gap junction 28 23 24
Mitochondrial translocase 39 36 42
Nucleoporin 39 36 27
Solute Carrier Family 454 404 430
Others + Unclassified 170 160 154
Total 1555 1422 1453
The Distribution of Human Transporter
Genes on Chromosomes

Users can click on the chromosome to see which transporters are in that region, or turn to the Chromosome page (under Distribution on the menu) for histogram of all categories in details.