Cathepsin C Propeptide Interacts with Intestinal Alkaline Phosphatase and Heat Shock Cognate Protein 70 in Human Caco-2 Cells

The Journal of Physiological Sciences

Katsuya Hirasaka³  Reiko Nakao³  Motoko Oarada¹  Kazumi Ishidoh²  Yuushi Okumura³  Kaori Tokuoka³  Takahito Imagawa²  Takeshi Nikawa³  Chiharu Yamada³  Kyoichi Kishi³ 

[1] Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University;The Institute for Health Sciences, Tokushima Bunri University;Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School

关键词: cathepsin C propeptide;    HSC-70;    human Caco-2 cells;    IAP;    sucrase;   

DOI  :  10.2170/physiolsci.RP013007

学科分类：生理学

来源: Springer

【 摘 要 】

References(30)Cited-By(3)The oligomeric structure and the residual propeptide are distinct characteristics of cathepsin C from other members in the papain superfamily. In this study, we examined the physiological role of the cathepsin C propeptide. The stable overexpression of cathepsin C propeptide significantly decreased the activities of intestinal alkaline phosphatase (IAP) and sucrase in human Caco-2 intestinal epithelial cells, whereas it did not change the proliferation and cathepsin C activity. The overexpression of cathepsin C propeptide significantly decreased the amounts of IAP protein in differentiated Caco-2 cells, compared with the transfection of mock vector, whereas the amounts of IAP transcripts were not changed. Pulse-chase analysis confirmed that the reduction in IAP activity was due to an increase in IAP degradation, but not a decrease in IAP expression. For the mechanism of the enhanced IAP degradation, we identified proteins interacting with cathepsin C propeptide in Caco-2 cells by immunoprecipitation and mass spectrometry. Cathepsin C propeptide interacted with proteins with a molecular mass of approximately 70 kDa, including IAP and heat shock cognate protein 70. Our present results suggest that the propeptide of cathepsin C may stimulate the sorting to the lysosome, at least in part, contributing to the degradation of IAP in Caco-2 cells.

【 授权许可】

Unknown