Researcher interests: Assembly and degradation processes in chloroplasts of higher plants. Proteolysis in chloroplasts. Proteolytic processes are involved in a wide range of functions throughout the life cycle of any cell. Chloroplast proteases are thus expected to affect photosynthesis at several different levels. The development of proplastids and etioplasts into chloroplasts involves not only the synthesis of a new set of proteins, but also massive degradation of the previous population. Gene expression within the chloroplast may require degradation of positive and negative regulators. Limited proteolytic processing is an essential step in the import and sorting of nuclear-encoded chloroplast proteins, and in the maturation of some chloroplast-encoded proteins. Proteases are likely to participate in the biogenesis of some protein complexes. Perhaps the most explored aspect of protein degradation in chloroplasts is its role in the response to changing environmental conditions. Increasing light intensities lead to photodamage, the repair of which requires accelerated removal of damaged proteins. Similarly, heat-denatured proteins that fail to refold properly are degraded. Using biochemical, molecular and genetic approaches, we have identified and characterized a number of chloroplast proteases in all major compartments of the organelle. In our current research we focus mainly on proteases of the FtsH and Deg families, and study their role in the biogenesis and maintenance of the photosynthetic apparatus.