Barley cysteine protease PAP14 plays a role in degradation of chloroplast proteins
| Autor: | Andrea Matros, Susann Frank, Julien Hollmann, Maria Mulisch, Karin Krupinska, Goetz Hensel, Hans-Peter Mock, Cristian C Carrión |
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| Rok vydání: | 2019 |
| Předmět: |
Proteases
HvPAP14 (CAQ00109.1) Chloroplasts Rubisco Physiology leaf senescence medicine.medical_treatment Plant Science Protein degradation Endoplasmic Reticulum Models Biological Substrate Specificity Chloroplast Proteins chloroplast thylakoid membranes Cysteine Proteases Barley medicine cysteine protease Protease Hordeum vulgare L Chemistry fungi food and beverages Hordeum Cell Biology Hydrogen-Ion Concentration Plants Genetically Modified Cysteine protease Research Papers Recombinant Proteins Chloroplast Plant Leaves Protein Transport Biochemistry Thylakoid Proteolysis Hordeum vulgare |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 |
| Popis: | HvPAP14 is a cysteine protease found in association with thylakoid membranes. Among its putative substrates are proteins such as LHCB1, LHCB5, PSBO, and RbcL, as revealed in overexpressing barley plants. Chloroplast protein degradation is known to occur both inside chloroplasts and in the vacuole. Genes encoding cysteine proteases have been found to be highly expressed during leaf senescence. However, it remains unclear where they participate in chloroplast protein degradation. In this study HvPAP14, which belongs to the C1A family of cysteine proteases, was identified in senescing barley (Hordeum vulgare L.) leaves by affinity enrichment using the mechanism-based probe DCG-04 targeting cysteine proteases and subsequent mass spectrometry. Biochemical analyses and expression of a HvPAP14:RFP fusion construct in barley protoplasts was used to identify the subcellular localization and putative substrates of HvPAP14. The HvPAP14:RFP fusion protein was detected in the endoplasmic reticulum and in vesicular bodies. Immunological studies showed that HvPAP14 was mainly located in chloroplasts, where it was found in tight association with thylakoid membranes. The recombinant enzyme was activated by low pH, in accordance with the detection of HvPAP14 in the thylakoid lumen. Overexpression of HvPAP14 in barley revealed that the protease can cleave LHCB proteins and PSBO as well as the large subunit of Rubisco. HvPAP14 is involved in the normal turnover of chloroplast proteins and may have a function in bulk protein degradation during leaf senescence. |
| Databáze: | OpenAIRE |
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