Molecular determinants of protein half-life in chloroplasts with focus on the Clp protease system.

Lioba Inken Winckler, Nico Dissmeyer

Biological chemistry 2023 Apr 25

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Proteolysis is an essential process to maintain cellular homeostasis. One pathway that mediates selective protein degradation and which is in principle conserved throughout the kingdoms of life is the N-degron pathway, formerly called the 'N-end rule'. In the cytosol of eukaryotes and prokaryotes, N-terminal residues can be major determinants of protein stability. While the eukaryotic N-degron pathway depends on the ubiquitin proteasome system, the prokaryotic counterpart is driven by the Clp protease system. Plant chloroplasts also contain such a protease network, which suggests that they might harbor an organelle specific N-degron pathway similar to the prokaryotic one. Recent discoveries indicate that the N-terminal region of proteins affects their stability in chloroplasts and provides support for a Clp-mediated entry point in an N-degron pathway in plastids. This review discusses structure, function and specificity of the chloroplast Clp system, outlines experimental approaches to test for an N-degron pathway in chloroplasts, relates these aspects into general plastid proteostasis and highlights the importance of an understanding of plastid protein turnover. © 2023 Walter de Gruyter GmbH, Berlin/Boston.

Citation

Lioba Inken Winckler, Nico Dissmeyer. Molecular determinants of protein half-life in chloroplasts with focus on the Clp protease system. Biological chemistry. 2023 Apr 25;404(5):499-511