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| | STEAP gene organization, mRNA transcripts and predicted protein structure. Green boxes correspond to exons. |
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| Description | 339 amino acids (NCBI: AF186249); MW 40kDa, contains 6 transmembrane helical domains (table 1) and a theoretical pI of 9.28. |
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| | Table 1-Sequence of the 6 transmembrane helices. |
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| Expression | Cell lines: Prostate-LnCAP, LAPC4, PC3, DU145, breast-MCF7, melanoma-624mel, 697mel, 888mel, MM331, gastrointestinal tract-MKN45, WiDR, lung-1355.
Normal murine tissues: bone marrow, brain, colon, duodenum, liver, heart, ileum, kidney, lung, pancreas, placenta, prostate, skeletal muscle, thymus, testis. |
| Localisation | Cell membrane. |
| Function | STEAP1 was first identified as a prostate-specific cell-surface antigen, over-expressed in human prostate cancer, and in the spontaneous transgenic mouse model of prostate cancer, by suppressive subtractive hybridization. It is also expressed in several human cancer cell lines obtained from prostate, breast, pancreas, bladder, gastrointestinal tract, testis, ovary, cervix, Ewing sarcoma, and melanomas, and in malignant tumours from several different tissues (eg. Prostate, breast, bladder, lung), with little or no expression in vital organs. Recent data showed that STEAP1 is involved in intercellular communication between adjacent cells in culture, and that it seems to favour tumour development. Its structure prediction, and location at cell-cell junctions, suggest that STEAP1 must be a channel, or a transport protein. Its cell surface location in all tumour types analyzed so far, and its absence in most vital organs in humans, turned STEAP1 into a potential target for anti-tumour immunotherapy, which has already been used in animal models of cancer with promising results. In addition, high levels of STEAP mRNA have been detected in the circulation of cancer patients increasing the potential of STEAP as a diagnosing marker for human cancer. |
| Homology | Highest levels of homology with the other members of the family in the following order: STEAP2, STEAP3 and STEAP4. |
| STEAP, a prostate tumor antigen, is a target of human CD8+ T cells. |
| Alves PM, Faure O, Graff-Dubois S, Cornet S, Bolonakis I, Gross DA, Miconnet I, Chouaib S, Fizazi K, Soria JC, Lemonnier FA, Kosmatopoulos K. |
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| PMID 16622681 |
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| Challita-Eid PM, Morrison K, Etessami S, An Z, Morrison KJ, Perez-Villar JJ, Raitano AB, Jia XC, Gudas JM, Kanner SB, Jakobovits A. |
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| PMID 17575147 |
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| Cancer Res. 2007 Feb 1;67(3):1344-51. |
| PMID 17283172 |
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| STEAP: a prostate-specific cell-surface antigen highly expressed in human prostate tumors. |
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| PMID 10588738 |
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| Recognition of prostate and melanoma tumor cells by six-transmembrane epithelial antigen of prostate-specific helper T lymphocytes in a human leukocyte antigen class II-restricted manner. |
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| PMID 17545632 |
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| PMID 16024648 |
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| STEAP1 is over-expressed in breast cancer and down-regulated by 17beta-estradiol in MCF-7 cells and in the rat mammary gland. |
| Maia CJ, Socorro S, Schmitt F, Santos CR. |
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| PMID 18958632 |
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| Clin Cancer Res. 2005 Jun 15;11(12):4545-52. |
| PMID 15958640 |
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| Yang D, Holt GE, Velders MP, Kwon ED, Kast WM. |
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| PMID 11479226 |
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