潘尼斯电池
胰蛋白酶
防御素
小肠
生物
生物化学
分子生物学
抗菌肽
细胞生物学
化学
肽
酶
作者
Dipankar Ghosh,Edith Porter,Bo Shen,Sarah K. Lee,Dennis Wilk,Judith A. Drazba,Satya Prakash Yadav,John W. Crabb,Tomas Ganz,Charles L. Bevins
摘要
The antimicrobial peptide human α-defensin 5 (HD5) is expressed in Paneth cells, secretory epithelial cells in the small intestine. Unlike other characterized defensins, HD5 is stored in secretory vesicles as a propeptide. The storage quantities of HD5 are ∼90–450 μg per cm2 of mucosal surface area, which is sufficient to generate microbicidal concentrations in the intestinal lumen. HD5 peptides isolated from the intestinal lumen are proteolytically processed forms—HD5(56–94) and HD5(63–94)—that are cleaved at the Arg55-Ala56 and Arg62-Thr63 sites, respectively. We show here that a specific pattern of trypsin isozymes is expressed in Paneth cells, that trypsin colocalizes with HD5 and that this protease can efficiently cleave HD5 propeptide to forms identical to those isolated in vivo. By acting as a prodefensin convertase in human Paneth cells, trypsin is involved in the regulation of innate immunity in the small intestine.
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