Proteome Analysis of a Hepatocyte-Specific BIRC5 (Survivin)-Knockout Mouse Model during Liver Regeneration

The Baculoviral IAP repeat-containing protein 5 (BIRC5), also known as inhibitor of apoptosis protein survivin, is a member of the chromosomal passenger complex and a key player in mitosis. To investigate the function of BIRC5 in liver regeneration, we analyzed a hepatocyte-specific BIRC5-knockout mouse model using a quantitative label-free proteomics approach. Here, we present the analyses of the proteome changes in hepatocyte-specific BIRC5-knockout mice compared to wildtype mice, as well as proteome changes during liver regeneration induced by partial hepatectomy in wildtype mice and mice lacking hepatic BIRC5, respectively. The BIRC5-knockout mice showed an extensive overexpression of proteins related to cellular maintenance, organization and protein synthesis. Key regulators of cell growth, transcription and translation MTOR and STAT1/STAT2 were found to be overexpressed. During liver regeneration proteome changes representing a response to the mitotic stimulus were detected in wildtype mice. Mainly proteins corresponding to proliferation, cell cycle and cytokinesis were up-regulated. The hepatocyte-specific BIRC5-knockout mice showed impaired liver regeneration, which had severe consequences on the proteome level. However, several proteins with function in mitosis were found to be up-regulated upon the proliferative stimulus. Our results show that the E3 ubiquitin-protein ligase UHRF1 is strongly up-regulated during liver regeneration independently of BIRC5

Diversity and Plasticity of Plastids in Land Plants

Plastids represent a largely diverse group of organelles in plant and algal cells that have several common features but also a broad spectrum of differences in respect of how they look (color, size, and ultrastructure), and what their specific function and molecular composition is. Plastids and their structural and metabolic diversity significantly contribute to the functionality and developmental flexibility of the plant body throughout its lifetime. In addition, to the multiple roles of given plastid types, this diversity is accomplished in some cases by interconversions between different plastids as a consequence of developmental and environmental signals that regulate plastid differentiation and specialization