Dubey Ved Prakash, De Prabir Kumar
Babasaheb Bhimrao Ambedkar Bihar University (BRABU), Muzaffarpur, 842001, Bihar, India.
Head and Senior Assistant Professor, Post Graduate Department of Zoology, Sri Radha Krishna Goenka College, Sitamarhi, 843302, Bihar, India.
Sci Rep. 2025 Aug 11;15(1):29393. doi: 10.1038/s41598-025-12831-9.
Lipocalins are abundantly expressed secretory proteins that perform diverse roles such as ligand-transport, immunomodulation, cell-signaling, chemical communication etc. In Syrian hamsters (Mesocricetus auratus), male-specific submandibular gland proteins (MSP) and female-specific lacrimal gland proteins (FLP) are sex-specifically secreted in saliva and tears respectively. MSP and FLP are lipocalins having 85% protein sequence identity between themselves and they have 58-61% identity with odorant-binding lipocalins (OBP) of rat and mouse. We purified natural MSP and FLP from hamster tissues and recombinant MSP and FLP after cloning and overexpression in E. coli. We found that MSP and FLP have very similar far ultraviolet-circular dichroic (UV-CD) spectra, typical of lipocalins. Natural MSP was found to be expressed as glycosylated and non-glycosylated forms and had no phosphorylation while FLP had no glycosylation or phosphorylation. In vitro ligand binding studies showed that MSP and FLP bind with high affinity to 2-isobutyl-3-methoxypyrazine (IBMP; a potent bell-pepper odorant) and also other test odorants. Therefore, we conclude that the sex-specific MSP and FLP lipocalins are odorant-binding proteins and they may have a role in odor-mediated communication in male and female hamsters.
脂质运载蛋白是大量表达的分泌蛋白，发挥着多种作用，如配体运输、免疫调节、细胞信号传导、化学通讯等。在叙利亚仓鼠（金黄仓鼠）中，雄性特异性下颌下腺蛋白（MSP）和雌性特异性泪腺蛋白（FLP）分别在唾液和泪液中特异性分泌。MSP和FLP是脂质运载蛋白，它们之间的蛋白质序列同一性为85%，与大鼠和小鼠的气味结合脂质运载蛋白（OBP）有58 - 61%的同一性。我们从仓鼠组织中纯化了天然MSP和FLP，并在大肠杆菌中克隆和过表达后获得了重组MSP和FLP。我们发现MSP和FLP具有非常相似的远紫外圆二色性（UV - CD）光谱，这是脂质运载蛋白的典型特征。天然MSP被发现以糖基化和非糖基化形式表达，且无磷酸化，而FLP无糖基化或磷酸化。体外配体结合研究表明，MSP和FLP与2 - 异丁基 - 3 - 甲氧基吡嗪（IBMP；一种强烈的甜椒气味剂）以及其他测试气味剂具有高亲和力结合。因此，我们得出结论，性别特异性的MSP和FLP脂质运载蛋白是气味结合蛋白，它们可能在雄性和雌性仓鼠的气味介导通讯中发挥作用。
