Breast Cancer Associated Gene 3 (BCA3)

The full-length protein contains 210 amino acids and has an N-terminal proline-rich domain, followed by 5 SH2 binding sites and a C-terminal PDZ type II binding sequence. It also has putative sites for phosphorylation by several protein kinases. The alternatively spliced transcripts lack either exon 3 or both exons 3 and 5 and encode proteins without some of the phosphorylation sites. RT-PCR detected variable expression of the 3 transcripts in breast and prostate cancer cell lines. Northern blot analysis detected highest BCA3 expression in heart, lower expression in testis, ovary, and skeletal muscle, and no expression in other normal tissues examined. Immunohistochemical staining of primary breast tumor tissues detected expression in invasive ductal carcinoma and in ductal carcinoma in situ.