Intra- and extracellular fates of the beta-defensin SPAG11C transiently expressed in cultured cells and the influence of a potential protein partner

Abstract

In the last years, our research group has identified different beta-defensins, key components of innate immunity, with a distinct expression pattern in the rat Wolffian duct (WD), the embryonic precursor of epididymis. We showed that the beta-defensin SPAG11C (sperm associated antigen 11 C) is an androgen-regulated mesenchymal factor with a role in epididymal morphogenesis. The research project currently developed by the graduate student Lucas G. Ferreira (FAPESP #2016/22118-1; Master level) is also investigating the androgen regulation and functional aspects of two other beta-defensins (DEFB1, beta-defensin 1; and DEFB2) with the goal to understand the potential differential effects of these beta-defensins on epididymal development. The knowledge on the subcellular localization of beta-defensins, as well as their functional association with protein partners in the WD and epididymis is essential for understanding their physiological function in this tissue. All beta-defensins contain in their primary structure a signal peptide that directs them to the secretory pathway but their cellular trafficking has been, however, scarcely investigated. Recently, we have established a collaborative partnership with the research team headed by Dr. A. Benham at Durham University, UK (SPRINT FAPESP #2015/50011-4) that has outstanding expertise in protein quality control and trafficking studies. Thus, the aim of this BEPE internship is to take advantage of the expertise and technologies in Dr. Benham's laboratory to study the localization, trafficking and cell secretion of recombinant beta-defensins transiently expressed in cultured cells. In line with the goals of Lucas G. Ferreira's sponsored FAPESP projects (#2016/00164-1 and #2016/22118-1), we selected the beta-defensin SPAG11C and its potential functional partner GLRX3 (small oxidoreductase glutaredoxin 3) for these studies. The results will be fundamental to better understand if a beta-defensin can be directed to different locations in the cell as a function of its co-expression with a protein partner and the role of innate immunity proteins on epididymal development and function.