{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nSperm lysozyme‐like protein 1 (SLLP1) is a specialized acrosomal protein that, despite its structural similarity to conventional c‐lysozymes, lacks bacteriolytic activity and plays a pivotal role during fertilization. SLLP1 is retained in the equatorial segment of acrosome-reacted sperm and promotes the binding of spermatozoa to the egg plasma membrane. Functional studies using recombinant SLLP1 and its inhibitory antibodies have shown that interference with SLLP1 significantly reduces sperm–oocyte binding and subsequent fertilization, underscoring its essential role in gamete recognition and fusion."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}, {"type": "p", "children": [{"type": "t", "text": "\nFurther elucidation of the molecular basis of fertilization revealed that SLLP1 interacts with a unique oocyte receptor, SAS1B—a membrane-associated metalloproteinase expressed exclusively in ovarian tissues. SAS1B localizes to the microvillar domain of oocytes where it binds SLLP1 with high affinity; disruption of this interaction, whether by protease inhibition or genetic knockout, results in impaired fertilization. These observations highlight the SLLP1–SAS1B pairing as a critical mediator of sperm–oocyte adhesion and fusion."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": ""}, {"type": "p", "children": [{"type": "t", "text": "\nComplementary structural and biochemical analyses further reveal that SLLP1 exhibits distinct modifications compared with conventional lysozymes, including substitutions at key catalytic residues and the presence of invariant surface “fingerprint” regions. These features, along with the formation of oligomeric helical assemblies, are thought to be important for its selective binding to SAS1B. Moreover, studies in bovine and murine models—as well as observations of autoantibody reactivity in infertile women—suggest that SLLP1 not only plays a role in sperm function but may also be involved in female fertility. This multifaceted role reinforces the significance of SLLP1 in ensuring successful gamete interaction and embryo viability."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}]}]}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "María Belén Herrero, Arabinda Mandal, Laura C Digilio, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Mouse SLLP1, a sperm lysozyme-like protein involved in sperm-egg binding and fertilization."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Dev Biol (2005)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.ydbio.2005.05.008"}], "href": "https://doi.org/10.1016/j.ydbio.2005.05.008"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "15982649"}], "href": "https://pubmed.ncbi.nlm.nih.gov/15982649"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Monika Sachdev, Arabinda Mandal, Sabine Mulders, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Oocyte specific oolemmal SAS1B involved in sperm binding through intra-acrosomal SLLP1 during fertilization."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Dev Biol (2012)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.ydbio.2011.12.021"}], "href": "https://doi.org/10.1016/j.ydbio.2011.12.021"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "22206759"}], "href": "https://pubmed.ncbi.nlm.nih.gov/22206759"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Angela Wagner, Olivia J Holland, Mancy Tong, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The role of SPRASA in female fertility."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Reprod Sci (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1177/1933719114542009"}], "href": "https://doi.org/10.1177/1933719114542009"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "25038051"}], "href": "https://pubmed.ncbi.nlm.nih.gov/25038051"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "H Zheng, A Mandal, I A Shumilin, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Sperm Lysozyme-Like Protein 1 (SLLP1), an intra-acrosomal oolemmal-binding sperm protein, reveals filamentous organization in protein crystal form."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Andrology (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1111/andr.12057"}], "href": "https://doi.org/10.1111/andr.12057"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "26198801"}], "href": "https://pubmed.ncbi.nlm.nih.gov/26198801"}]}]}]}