scholarly journals Role of Temperature Stress on Chloroplast Biogenesis and Protein Import in Pea

2009 ◽  
Vol 150 (2) ◽  
pp. 1050-1061 ◽  
Author(s):  
Siddhartha Dutta ◽  
Sasmita Mohanty ◽  
Baishnab C. Tripathy
Keyword(s):  
Temperature Stress ◽  
Protein Import ◽  
Chloroplast Biogenesis

scholarly journals The Role of Tetrapyrrole- and GUN1-Dependent Signaling on Chloroplast Biogenesis

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 196
Author(s):  
Takayuki Shimizu ◽  
Tatsuru Masuda
Keyword(s):  
Protein Import ◽  
Nuclear Gene ◽  
Retrograde Signaling ◽  
Chloroplast Biogenesis ◽  
Plastid Development ◽  
Nuclear Gene Expression ◽  
Coordinated Expression ◽  
Plastid Protein ◽  
Working Hypotheses

Chloroplast biogenesis requires the coordinated expression of the chloroplast and nuclear genomes, which is achieved by communication between the developing chloroplasts and the nucleus. Signals emitted from the plastids, so-called retrograde signals, control nuclear gene expression depending on plastid development and functionality. Genetic analysis of this pathway identified a set of mutants defective in retrograde signaling and designated genomes uncoupled (gun) mutants. Subsequent research has pointed to a significant role of tetrapyrrole biosynthesis in retrograde signaling. Meanwhile, the molecular functions of GUN1, the proposed integrator of multiple retrograde signals, have not been identified yet. However, based on the interactions of GUN1, some working hypotheses have been proposed. Interestingly, GUN1 contributes to important biological processes, including plastid protein homeostasis, through transcription, translation, and protein import. Furthermore, the interactions of GUN1 with tetrapyrroles and their biosynthetic enzymes have been revealed. This review focuses on our current understanding of the function of tetrapyrrole retrograde signaling on chloroplast biogenesis.

scholarly journals Essential role of the G-domain in targeting of the protein import receptor atToc159 to the chloroplast outer membrane

2002 ◽  
Vol 159 (5) ◽  
pp. 845-854 ◽  
Author(s):  
Jörg Bauer ◽  
Andreas Hiltbrunner ◽  
Petra Weibel ◽  
Pierre-Alexandre Vidi ◽  
Mayte Alvarez-Huerta ◽  
...  
Keyword(s):  
Fusion Proteins ◽  
Essential Role ◽  
Protein Import ◽  
Chloroplast Envelope ◽  
Chloroplast Biogenesis ◽  
Gtp Binding ◽  
Precursor Proteins ◽  
Albino Mutant ◽  
Import Receptor

Two homologous GTP-binding proteins, atToc33 and atToc159, control access of cytosolic precursor proteins to the chloroplast. atToc33 is a constitutive outer chloroplast membrane protein, whereas the precursor receptor atToc159 also exists in a soluble, cytosolic form. This suggests that atToc159 may be able to switch between a soluble and an integral membrane form. By transient expression of GFP fusion proteins, mutant analysis, and biochemical experimentation, we demonstrate that the GTP-binding domain regulates the targeting of cytosolic atToc159 to the chloroplast and mediates the switch between cytosolic and integral membrane forms. Mutant atToc159, unable to bind GTP, does not reinstate a green phenotype in an albino mutant (ppi2) lacking endogenous atToc159, remaining trapped in the cytosol. Thus, the function of atToc159 in chloroplast biogenesis is dependent on an intrinsic GTP-regulated switch that controls localization of the receptor to the chloroplast envelope.

scholarly journals Molecular Dynamics of Chloroplast Membranes Isolated from Wild-Type Barley and a Brassinosteroid-Deficient Mutant Acclimated to Low and High Temperatures

Biomolecules ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 27
Author(s):  
Iwona Sadura ◽  
Dariusz Latowski ◽  
Jana Oklestkova ◽  
Damian Gruszka ◽  
Marek Chyc ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Temperature Stress ◽  
High Temperatures ◽  
Biological Membrane ◽  
Hydrophobic Core ◽  
Wild Type ◽  
Chloroplast Membranes ◽  
Paramagnetic Resonance ◽  
Photosynthetic Membranes

Plants have developed various acclimation strategies in order to counteract the negative effects of abiotic stresses (including temperature stress), and biological membranes are important elements in these strategies. Brassinosteroids (BR) are plant steroid hormones that regulate plant growth and development and modulate their reaction against many environmental stresses including temperature stress, but their role in modifying the properties of the biological membrane is poorly known. In this paper, we characterise the molecular dynamics of chloroplast membranes that had been isolated from wild-type and a BR-deficient barley mutant that had been acclimated to low and high temperatures in order to enrich the knowledge about the role of BR as regulators of the dynamics of the photosynthetic membranes. The molecular dynamics of the membranes was investigated using electron paramagnetic resonance (EPR) spectroscopy in both a hydrophilic and hydrophobic area of the membranes. The content of BR was determined, and other important membrane components that affect their molecular dynamics such as chlorophylls, carotenoids and fatty acids in these membranes were also determined. The chloroplast membranes of the BR-mutant had a higher degree of rigidification than the membranes of the wild type. In the hydrophilic area, the most visible differences were observed in plants that had been grown at 20 °C, whereas in the hydrophobic core, they were visible at both 20 and 5 °C. There were no differences in the molecular dynamics of the studied membranes in the chloroplast membranes that had been isolated from plants that had been grown at 27 °C. The role of BR in regulating the molecular dynamics of the photosynthetic membranes will be discussed against the background of an analysis of the photosynthetic pigments and fatty acid composition in the chloroplasts.

scholarly journals TOM20-mediated transfer of Bcl2 from ER to MAM and mitochondria upon induction of apoptosis

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Lisenn Lalier ◽  
Vincent Mignard ◽  
Marie-Pierre Joalland ◽  
Didier Lanoé ◽  
Pierre-François Cartron ◽  
...  
Keyword(s):  
Protein Import ◽  
Glioma Cells ◽  
Mitochondrial Outer Membrane ◽  
Mitochondrial Localization ◽  
Antiapoptotic Protein ◽  
Mitochondrial Transfer ◽  
Small Domain ◽  
Induction Of Apoptosis ◽  
And Function

AbstractIn this work, we have explored the subcellular localization of Bcl2, a major antiapoptotic protein. In U251 glioma cells, we found that Bcl2 is localized mainly in the ER and is translocated to MAM and mitochondria upon induction of apoptosis; this mitochondrial transfer was not restricted to the demonstrator cell line, even if cell-specific modulations exist. We found that the Bcl2/mitochondria interaction is controlled by TOM20, a protein that belongs to the protein import machinery of the mitochondrial outer membrane. The expression of a small domain of interaction of TOM20 with Bcl2 potentiates its anti-apoptotic properties, which suggests that the Bcl2–TOM20 interaction is proapoptotic. The role of MAM and TOM20 in Bcl2 apoptotic mitochondrial localization and function has been confirmed in a yeast model in which the ER–mitochondria encounter structure (ERMES) complex (required for MAM stability in yeast) has been disrupted. Bcl2–TOM20 interaction is thus an additional player in the control of apoptosis.

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