Major component of the transverse filaments of synaptonemal complexes, formed between homologous chromosomes during meiotic prophase. Required for normal assembly of the central element of the synaptonemal complexes. Required for normal centromere pairing during meiosis. Required for normal meiotic chromosome synapsis during oocyte and spermatocyte development and for normal male and female fertility. Structural component of synaptonemal complexes (By similarity). Homotetramer that consists of an N-terminal four-helical bundle that bifurcates into two elongated C-terminal dimeric coiled coils (PubMed:29915389, PubMed:26323297). This tetrameric building block potentially self-assembles into a supramolecular zipper-like lattice to mediate meiotic chromosome synapsis. Self-assembly is likely initiated by local proton density at chromosome axis, which is predicted to trigger antiparallel back to back assembly of adjacent C-terminal ends into tetrameric structures that anchor to chromosomal DNA. Then the N-terminal ends are predicted to undergo cooperative antiparallel head to head assembly at the midline of synaptonemal complexes central element to form a zipper-like lattice between properly aligned homologous chromosomes (PubMed:29915389). The nascent synapsis generated by SYCP1 is stabilized through interaction with central element proteins SYCE1 and SYCE2 (By similarity). Forms a complex with EWSR1, PRDM9, SYCP3 and REC8; complex formation is dependent of phosphorylated form of REC8 and requires PRDM9 bound to hotspot DNA; EWSR1 joins PRDM9 with the chromosomal axis through REC8 (By similarity). Interacts with SPO16 (By similarity). In tripartite segments of synaptonemal complexes, between lateral elements in the nucleus. Its N-terminus is found towards the center of the synaptonemal complex while the C-terminus extends well into the lateral domain of the synaptonemal complex (By similarity). Only rarely detected at centromeres during leptotene and zygotene. Detected at centromeres during mid-diplotene, when it is no longer present along chromosome arms. No longer detected at centromeres at later stages of meiosis (By similarity). Testis. The molecule is in a coiled coil structure that is formed by 4 polypeptide chains. The N-terminal and C-terminal regions exhibit a prominent seven-residues periodicity.