scholarly journals Tic21 Is an Essential Translocon Component for Protein Translocation across the Chloroplast Inner Envelope Membrane

2006 ◽  
Vol 18 (9) ◽  
pp. 2247-2257 ◽  
Author(s):  
Yi-Shan Teng ◽  
Yi-shin Su ◽  
Lih-Jen Chen ◽  
Yong Jik Lee ◽  
Inhwan Hwang ◽  
...  
Keyword(s):  
Protein Translocation ◽  
Envelope Membrane ◽  
Inner Envelope

Arabidopsis thaliana Tic110, involved in chloroplast protein translocation, contains at least fourteen highly divergent heat-like repeated motifs

Biologia ◽  
2014 ◽  
Vol 69 (2) ◽  
Author(s):  
Jorge Hernández-Torres ◽  
Adrián Jaimes-Becerra ◽  
Jacques Chomilier
Keyword(s):  
Protein Translocation ◽  
Protein Complexes ◽  
Nuclear Genome ◽  
Photosynthetic Bacterium ◽  
Eukaryotic Cell ◽  
Signal Peptides ◽  
Envelope Membrane ◽  
Transit Peptides ◽  
Repeated Motifs ◽  
Inner Envelope

AbstractEndosymbiotic theory suggests that plastids originated from a photosynthetic bacterium that was engulfed by a primitive eukaryotic cell. In consequence, the chloroplast genome remains affected by this ancestral event, although it is reduced in size and the number of constituent genes. Most parts of the plastid genome have been transferred to the host cell nuclear genome and are nuclear-encoded. Thus, chloroplast proteins are synthesized in the cytosol as precursors with N-terminal extensions called transit peptides. The evolution of import machinery was required to transfer transit peptides to the stroma. Until the present, two protein complexes have been found to mediate the import process: the Toc (outer) and Tic (inner) envelope membrane translocons. The evolutionary origin of many Tic and Toc proteins has been established, but not for the Tic110 subunit. Tic110 binds signal peptides and serves as a scaffold for the recruitment of stromal components. In this study, we analyzed hydrophobic clusters, protein folds, and protein structure homology and we conclude that Tic110 is composed of fourteen repeated motifs related to HEAT-repeats. The explanation for the presence of such repeats in Tic110 is that membrane arrangement is found in separate domains and their probable function in the chloroplast import process is discussed.

Arabidopsis ORANGE protein regulates plastid pre-protein import through interacting with Tic proteins

2020 ◽  
Author(s):  
Hui Yuan ◽  
Emily G Pawlowski ◽  
Yong Yang ◽  
Tianhu Sun ◽  
Theodore W Thannhauser ◽  
...  
Keyword(s):  
Turnover Rate ◽  
Protein Import ◽  
Protein Translocation ◽  
Carotenoid Biosynthesis ◽  
Envelope Membrane ◽  
Core Complex ◽  
The Core ◽  
Core Components ◽  
Orange Protein ◽  
Inner Envelope

Abstract Chloroplast-targeted proteins are actively imported into chloroplasts via the machinery spanning the double-layered membranes of chloroplasts. While the key translocons at the outer (TOC) and inner (TIC) membranes of chloroplasts are defined, proteins that interact with the core components to facilitate pre-protein import are continuously being discovered. A DnaJ-like chaperone ORANGE (OR) protein is known to regulate carotenoid biosynthesis as well as plastid biogenesis and development. In this study, we found that OR physically interacts with several Tic proteins including Tic20, Tic40, and Tic110 in the classic TIC core complex of the chloroplast import machinery. Knocking out or and its homolog or-like greatly affects the import efficiency of some photosynthetic and non-photosynthetic pre-proteins. Consistent with the direct interactions of OR with Tic proteins, the binding efficiency assay revealed that the effect of OR occurs at translocation at the inner envelope membrane (i.e. at the TIC complex). OR is able to reduce the Tic40 protein turnover rate through its chaperone activity. Moreover, OR was found to interfere with the interaction between Tic40 and Tic110, and reduces the binding of pre-proteins to Tic110 in aiding their release for translocation and processing. Our findings suggest that OR plays a new and regulatory role in stabilizing key translocons and in facilitating the late stage of plastid pre-protein translocation to regulate plastid pre-protein import.

scholarly journals Arabidopsis Tic40 Expression in Tobacco Chloroplasts Results in Massive Proliferation of the Inner Envelope Membrane and Upregulation of Associated Proteins

2008 ◽  
Vol 20 (12) ◽  
pp. 3405-3417 ◽  
Author(s):  
Nameirakpam Dolendro Singh ◽  
Ming Li ◽  
Sueng-Bum Lee ◽  
Danny Schnell ◽  
Henry Daniell
Keyword(s):  
Envelope Membrane ◽  
Associated Proteins ◽  
Inner Envelope

scholarly journals CV-containing vesicle budding from chloroplast inner envelope membrane is mediated by clathrin but inhibited by GAPC

2021 ◽  
Author(s):  
Ting Pan ◽  
Yangxuan Liu ◽  
Chengcheng Ling ◽  
Yuying Tang ◽  
Wei Tang ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Abiotic Stress ◽  
Water Stress ◽  
Stress Response ◽  
Eukaryotic Cells ◽  
Envelope Membrane ◽  
Vesicle Budding ◽  
Cargo Transport ◽  
Membrane Defects ◽  
Inner Envelope

AbstractClathrin-mediated vesicular formation and trafficking are highly conserved in eukaryotic cells and are responsible for molecular cargo transport and signal transduction among organelles. It remains largely unknown whether clathrin-coated vesicles can be generated from chloroplasts. CHLOROPLAST VESICULATION (CV)-containing vesicles (CVVs) generate from chloroplasts and mediate chloroplast degradation under abiotic stress. In this study, we showed that CV interacted with the clathrin heavy chain (CHC) and induced vesicle budding from the chloroplast inner envelope membrane. Defects on CHC2 and the dynamin-encoding DRP1A gene affected CVV budding and releasing from chloroplast. CHC2 is also required for CV-induced chloroplast degradation and hypersensitivity to water stress. Moreover, GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAPC) interacts with CV and impairs the CV-CHC2 interaction. GAPC1 overexpression inhibited CV-mediated chloroplast degradation and hypersensitivity to water stress. CV silencing alleviated the hypersensitivity of gapc1gapc2 plant to water stress. Together, our work revealed a pathway of clathrin-assisted CVV budding from the chloroplast inner envelope membrane, which mediated the stress-induced chloroplast degradation and stress response.

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