Transcription factor maybe involved in reproductive processes. Modulates expression of target genes encoding proteins involved in processes relevant to spermatogenesis. Does not interact with itself. Ovary, testis and epididymis. Also detected in the prostate and the mammary gland. Expressed in many tumor cell lines derived from acute lymphocytic leukemia, prostate, endometrial adenocarcinoma, melanoma, bladder carcinoma, colon carcinoma, erythroleukemia and breast carcinoma. Not expressed in placenta. In testis, mainly expressed in germ cells, but also detected in somatic cells such as Sertoli cells, Leydig cells and peritubular cells (PubMed:28171660). Predominantly expressed in late stage germ cells, pachytene spermatocytes and round spermatides. By androgen. Mutagenesis of amino acids 147 to 164 and 155 to 164 lead to a major cytoplasmic localization, with only minor localization in the nucleus. Belongs to the paired-like homeobox family. PEPP subfamily.