Chen L M, Skinner M L, Kauffman S W, Chao J, Chao L, Thaler C D, Chai K X
Department of Molecular Biology, University of Central Florida, Orlando, Florida 32816, USA.
J Biol Chem. 2001 Jun 15;276(24):21434-42. doi: 10.1074/jbc.M011423200. Epub 2001 Mar 26.
A recombinant human prostasin serine protease was expressed in several human cell lines. Subcellular fractionation showed that this serine protease is synthesized as a membrane-bound protein while a free-form prostasin is secreted into the culture medium. Prostasin was identified in nuclear and membrane fractions. Membrane-bound prostasin can be released by phosphatidylinositol-specific phospholipase C treatment, or labeled by [(3)H]ethanolamine, indicating a glycosylphosphatidylinositol anchorage. A prostasin-binding protein was identified in mouse and human seminal vesicle fluid. Both the secreted and the membrane-bound prostasin were able to form a covalently linked 82-kDa complex when incubated with seminal vesicle fluid. The complex formation between prostasin and the prostasin-binding protein was inhibited by a prostasin antibody, heparin, and serine protease inhibitors. Prostasin's serine protease activity was inhibited when bound to the prostasin-binding protein in mouse seminal vesicle fluid. This study indicates that prostasin is an active serine protease in its membrane-bound form.
重组人前列腺素丝氨酸蛋白酶在多种人类细胞系中表达。亚细胞分级分离显示，这种丝氨酸蛋白酶以膜结合蛋白的形式合成，而游离形式的前列腺素则分泌到培养基中。在细胞核和膜组分中鉴定出了前列腺素。膜结合的前列腺素可通过磷脂酰肌醇特异性磷脂酶C处理释放，或用[³H]乙醇胺标记，表明其为糖基磷脂酰肌醇锚定。在小鼠和人类精囊液中鉴定出一种前列腺素结合蛋白。当分泌型和膜结合型前列腺素与精囊液一起孵育时，两者都能形成共价连接的82 kDa复合物。前列腺素与前列腺素结合蛋白之间的复合物形成受到前列腺素抗体、肝素和丝氨酸蛋白酶抑制剂的抑制。当与小鼠精囊液中的前列腺素结合蛋白结合时，前列腺素的丝氨酸蛋白酶活性受到抑制。这项研究表明，前列腺素在其膜结合形式下是一种活性丝氨酸蛋白酶。
