Recruited co-dependently with zhp-3 to the synaptonemal complex between homologous chromosome pairs to regulate the formation and number of crossover events between homologs during meiotic recombination (PubMed:29521627, PubMed:30379819). In the early stages of pachytene, in complex with zhp-4, recruited by the zhp-1-zhp-2 heterodimer to designated crossover sites along the recombination intermediate to stabilize other pro-crossover factors such as rmh-1, msh-5 and cosa-1 (PubMed:29521627, PubMed:30379819). This in turn facilitates crossover and promotes the formation of chiasma in each meiotic nucleus at the late pachytene stage of meiosis (PubMed:29521627, PubMed:30379819). Negatively regulates double strand break formation to promote formation of the crossover intermediate (PubMed:30379819). Interacts with zhp-3; the interaction is required for their localization along paired chromosomes and stability, and for the formation of chiasma during meiotic recombination. Co-localizes with zhp-3 to chromosomes from mitosis to early diakinesis in the germline (PubMed:29521627, PubMed:30379819). Co-localizes with syp-1, a component of the synaptonemal complex from early prophase to mid-pachytene (PubMed:29521627, PubMed:30379819). At late pachytene, localization at chromosomes is not dependent on syp-1 (PubMed:29521627). From mid-pachytene, co-localizes with cosa-1 at crossover sites of recombination intermediates, and gradually disassociates from syp-1 along both chromosome arms (PubMed:29521627, PubMed:30379819). Expressed in the germline.