TSKS is a 592 amino acid protein that is highly expressed in human testicular tissue. Low levels of TSKS are detectable in prostate, placenta, fetal liver, thymus, and mammary gland tissues. TSKS is found to be downregulated in cancerous testicular tissue from seminoma, teratocarcinoma, embryonal and Leydig cell tumors concurrently with high expression in neighboring premalignant carcinoma. TSKS protein contains an N-terminal signal peptide, but does not contain a transmembrane region. TSKS has many potential phosphorylation and glycosylation sites and is phosphorylated by soluble recombinant TSSK2 in vitro. It is thought that TSKS likely plays a physiological role in spermatogenesis or spermiogenesis.