Component of the synapsis initiation complex (SIC) necessary for the synaptonemal complex assembly. Stabilizes the ZIP2 component to the chromosomes. The SIC complex loads onto chromosomes and nucleates ZIP1 polymerization; a molecular zipper that acts to bring homologous chromosomes in close apposition; which is required for meiotic crossover. May also be involved in double strand break repair. {ECO:0000269|PubMed:10454593; ECO:0000269|PubMed:10943844; ECO:0000269|PubMed:15035982; ECO:0000269|PubMed:15070750; ECO:0000269|PubMed:15805472}.