Alternative titles; symbols
Cytogenetic location: 7p14.1 Genomic coordinates (GRCh38) : 7:38,259,643-38,273,636 (from NCBI)
The TARP gene is embedded within an intron of the T-cell receptor-gamma (TCRG; see 186970) locus, which encodes an alternative T-cell receptor that is always coexpressed with T-cell receptor-delta (TCRD; see 186810). Although the TARP and TCRG proteins are distinct, TARP mRNA is detected by cDNA probes that detect TCRG. Unlike TCRG, however, TARP is detected in prostate cancer libraries in the absence of TCRD. TARP is upregulated by androgen (Maeda et al., 2004).
Essand et al. (1999) identified expression of a prostate-specific form of TCRG mRNA in human prostate and demonstrated that it originated from epithelial cells and not from infiltrating T lymphocytes. Wolfgang et al. (2000) found that this prostate-specific transcript was also expressed in 3 breast cancer cell lines and breast cancer tissues. Analysis of the cDNA sequence predicted that the transcript can encode protein products of 7 and 13 kD. In vitro translation experiments showed that both proteins were made. The longer ORF encodes a 13-kD truncated version of TCRG, whereas the shorter ORF encodes a novel 7-kD protein containing 58 amino acids, including 5 leucines in heptad repeats followed by a basic region. Studies with specific antibodies against each protein demonstrated that prostate and breast cancer cells contained only the 7-kD protein, which was located in the nucleus. Wolfgang et al. (2000) named this protein TARP. The results demonstrated that an alternative protein product is encoded by the TCRG locus in cells other than T lymphocytes.
Using subcellular fractionation, immunocytochemistry, and Western blot analysis, Maeda et al. (2004) found that TARP was upregulated by androgen in the mitochondria of prostate cell lines. Fractionation of mitochondria and immunohistochemistry indicated that TARP was located in the outer mitochondrial membrane. Maeda et al. (2004) proposed that TARP may act on mitochondria to carry out its biologic function.
Wolfgang et al. (2000) determined that the TARP gene contains 4 exons. The protein is encoded by exon 2.
Essand et al. (1999) determined that the TARP gene is embedded within an intron upstream of the joining gamma-1.2 (J gamma-1.2) segment of the TCRG locus on chromosome 7p15-p14.
Essand, M., Vasmatzis, G., Brinkmann, U., Duray, P., Lee, B., Pastan, I. High expression of a specific T-cell receptor gamma-transcript in epithelial cells of the prostate. Proc. Nat. Acad. Sci. 96: 9287-9292, 1999. [PubMed: 10430935] [Full Text: https://doi.org/10.1073/pnas.96.16.9287]
Maeda, H., Nagata, S., Wolfgang, C. D., Bratthauer, G. L., Bera, T. K., Pastan, I. The T cell receptor gamma chain alternate reading frame protein (TARP), a prostate-specific protein localized in mitochondria. J. Biol. Chem. 279: 24561-24568, 2004. [PubMed: 15150260] [Full Text: https://doi.org/10.1074/jbc.M402492200]
Wolfgang, C. D., Essand, M., Vincent, J. J., Lee, B., Pastan, I. TARP: a nuclear protein expressed in prostate and breast cancer cells derived from an alternate reading frame of the T cell receptor gamma-chain locus. Proc. Nat. Acad. Sci. 97: 9437-9442, 2000. [PubMed: 10931945] [Full Text: https://doi.org/10.1073/pnas.160270597]