Component of the transverse filaments of synaptonemal complexes (SCS); formed between homologous chromosomes during meiotic prophase. Required for axial elements (AE) in meiotic cells and for assembly of the synaptonemal complex. May be important for testis development and male fertility. Required for efficient phosphorylation of HORMAD1 and HORMAD2. {ECO:0000269|PubMed:10678170; ECO:0000269|PubMed:22346761}.