As a probable component of the LINC (LInker of Nucleoskeleton and Cytoskeleton) complex, involved in the connection between the nuclear lamina and the cytoskeleton. The nucleocytoplasmic interactions established by the LINC complex play an important role in the transmission of mechanical forces across the nuclear envelope and in nuclear movement and positioning. May be involved in nuclear remodeling during sperm head formation in spermatogenesis. A probable SUN3:SYNE1 LINC complex may tether spermatid nuclei to posterior cytoskeletal structures such as the manchette. Self-associates. Interacts with SYNE1 and SPAG4/SUN4. Proposed to form a spermatogenesis-specific LINC complex with SYNE1 during sperm head formation possibly implicating a SUN domain-based heterotrimer with SPAG4/SUN4 associating with SYNE1. The short coiled coil domain is proposed to be not involved in load-bearing and force transmission from the cytoskeleton but in mere nucleus anchorage instead. Truncated N-terminus.