May be involved in the regulation of spermatogenesis. Stimulates CREM transcriptional activity in a phosphorylation-independent manner (By similarity). Interacts with CREM (via the third LIM domain) (PubMed:10086359). Interacts (via second LIM domain) with SPAG8 (PubMed:20488182). Nuclei of round and elongated spermatids. Testis-specific, temporal expression is coordinated with CREM.