Multisubunit complex eEF1H in human glial tumors: from mRNA to protein

Aim. To investigate protein level of all subunits of the eukaryotic elongation translation factor eEF1H (eEF1A, eEF1Bα, eEF1Bβand eEF1Bγ) in glial tumors of human brain in comparison with normal brain. Methods. The eEF1H components content has been investigated in human glioblastoma clinical samples by Western blot analysis. Results. To determine the eEF1Bα, eEF1Bβ and eEF1Bγ content, the polyclonal antibodies against all eEF1H subunits were obtained. The tendency of the eEF1Bγ protein level to increase in glioblastomas was observed. There were no significant differences in the eEF1A, eEF1Bα and eEF1Bβ protein contents. Conclusions. In the previous report we analysed the expression of all eEF1H subunits in human glial brain tumor on the mRNA level. This study showed that eEF1Bγ was overexpressed while no significant changes in other eEF1H subunits were observed. It suggests a possible function of eEFBg which is cancer-related and is not connected with the functioning of eEF1H complex in translation

Translation elongation

The synthesis of proteins in eukaryotes is typically divided into four steps, i.e. initiation, elongation, termination and ribosome recycling. This key biological event is tightly regulated by the cell. Under conditions of increased demand or reduced production of cellular energy the cell can downregulate this process. While a tight regulation exists for the rate-limiting initiation step, elongation also appears to be under somewhat strict control. Among key targets of elongation regulation are the eukaryotic elongation factors A1/A2 (eEF1A1/A2) and the eukaryotic elongation factor 2 (eEF2). In addition to being involved in the regulation of protein synthesis, evidence indicates that these factors play a relevant role in the genesis and maintenance of many forms of human cancers. For this reason, elongation factors have been considered as valuable markers for different forms of cancers, as well as attractive candidates for targeted anticancer therapeutic approaches. In this chapter we focus on the description of the factors taking part in the process of elongation, as well as their involvement in cancer. Particular emphasis is put on the description of (1) the physiological role of elongation factors in elongation and in other biological processes; (2) the control of elongation factors by signaling pathways; (3) the involvement of elongation factors in cancer and (4) the anticancer therapeutic approaches based on the targeting of elongation factors