Cathepsin B/X is secreted by Echinometra lucunter sea urchin spines, a structure rich in granular cells and toxins

Journal of venomous animals and toxins

Adriana da Costa Neves¹  Juliana Mozer Sciani²  Daniel Carvalho Pimenta⁴  Marta Maria Antoniazzi⁵ 

[1]Center of Marine Biology, University of Sã

[2]Laboratory of Biochemistry and Biophysics, Butantan Institute, Sã

[3]Laboratory of Cell Biology, Butantan Institute, Sã

[4]o Paulo (USP), Sã

[5]o Paulo, Brazil

[6]o Sebastiã

[7]o, Brazil

关键词: Echinometra lucunter;    Spines;    Cathepsin;    Proteolysis;   

DOI  :  10.1186/1678-9199-19-33

学科分类：药理学

来源: BioMed Central

【 摘 要 】

Echinometra lucunter is a common American sea urchin responsible for the majority of the marine accidents in Brazil. Although not lethal, these accidents are reported to be extremely painful. Recently, our group described the presence of toxins in its spines that contribute to the pathological reactions. Additionally, we have observed that the E. lucunter spines can regenerate when broken. In the present work we evaluated the enzymatic activities of sea urchin spine extracts in order to identify an enzyme that could contribute not only to the toxicity, but also participate in the spine growth and regeneration. The spine aqueous extract was tested for peptidase activity, with synthetic substrates, in the presence and absence of inhibitors and activators. For proper enzyme classification, the FRET-substrate cleavage pattern, pH-dependency activity and Western-blot analyses were performed. The spine extract was able to cleave Z-R-MCA and Abz-GIVRAK(Dnp)-OH following pre-incubation with DTT, and was inhibited by E-64. Furthermore, the double-peaked pH curve (5 and 7) and the cleavage site proportion (4:6, R↓A:A↓K) indicate the presence of both mono and dicarboxypeptidase activities. Moreover, in Western-blot analysis, the spine extract was positive for anti-cathepsin B antibody. E. lucunter spines extracts presented a cysteine peptidase activity that was identified as cathepsin B/X that would participate in the remodeling and growth processes of the spine, as well as in the inflammatory response to the accident.

【 授权许可】

CC BY