Mechanism and role of ILEI dimerization in tumor progression
The ILEI protein bears complex posttranslational structural modifications. It is present in monomers and covalent, disulfide bond-mediated dimers both intra- and extracellular. The cysteine, identified to mediate dimerization, is essential for ILEI-dependent elevated tumor growth (Figure 1). The further characterization of this modification, its role in ILEI function and its molecular regulatory mechanisms will help us to identify crucial features of the active form of the protein. In addition, identification of key enzymes (protein disulfide isomerases) regulating ILEI dimerization will provide novel therapeutic considerations of ILEI-dependent tumor progression.
Figure 1. ILEI dimerization is essential for elevated tumor growth. Primary tumor growth capacity of EpC40 murine mammary tumor cells overexpressing empty vector (cont.), wild type (ILEIwt) or dimerization mutant (ILEICA) forms of ILEI was determined upon mammary gland fat pad injection (n=5 mice per group). A) Tumor growth was monitored by regular measurement and volume calculation. B) Tumor masses were determined 43 days after injection.