ATP‐dependent proteases in plant mitochondria: What do we know about them today?

Jańska, Hanna

doi:10.1111/j.1399-3054.2004.00439.x

Cited by 33 publications

(32 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These proteases are indeed encoded in Arabidopsis and have been shown to participate in protein degradation [95][96][97]. The mitochondrial protein degradation system is also associated with the anther-specific accumulation of the CMS-associated ORF239 polypeptide in the common bean [98].…”

Section: Why Do Most Of the Unique Orfs Not Matter In Angiosperm Mitomentioning

confidence: 99%

Cost of Having the Largest Mitochondrial Genome: Evolutionary Mechanism of Plant Mitochondrial Genome

Kitazaki

Kubo

2010

Journal of Botany

View full text Add to dashboard Cite

The angiosperm mitochondrial genome is the largest and least gene-dense among the eukaryotes, because its intergenic regions are expanded. There seems to be no functional constraint on the size of the intergenic regions; angiosperms maintain the large mitochondrial genome size by a currently unknown mechanism. After a brief description of the angiosperm mitochondrial genome, this review focuses on our current knowledge of the mechanisms that control the maintenance and alteration of the genome. In both processes, the control of homologous recombination is crucial in terms of site and frequency. The copy numbers of various types of mitochondrial DNA molecules may also be controlled, especially during transmission of the mitochondrial genome from one generation to the next. An important characteristic of angiosperm mitochondria is that they contain polypeptides that are translated from open reading frames created as byproducts of genome alteration and that are generally nonfunctional. Such polypeptides have potential to evolve into functional ones responsible for mitochondrially encoded traits such as cytoplasmic male sterility or may be remnants of the former functional polypeptides.

show abstract

Section: Why Do Most Of the Unique Orfs Not Matter In Angiosperm Mitomentioning

confidence: 99%

Cost of Having the Largest Mitochondrial Genome: Evolutionary Mechanism of Plant Mitochondrial Genome

Kitazaki

Kubo

2010

Journal of Botany

View full text Add to dashboard Cite

show abstract

“…However, these major proteasome pathways are not directly available to turnover proteins in intraorganellar environments. Therefore, mitochondria, chloroplasts, and peroxisomes possess alternate pathways governed by networks of chaperone and protease functions for the maintenance of protein homeostasis.The AAA + protease class (ATPases associated with diverse cellular activities) of proteases (Neuwald et al, 1999;Ogura and Wilkinson, 2001) are largely responsible for this organellar protein homeostasis in plants (Janska, 2005). The ATP-dependent proteases (including the Clp, FtsH, and Lon subclasses) are multimeric ring structures (Lupas et al, 1997;Schmidt et al, 1999) that selectively bind a substrate, unfold, and translocate the substrate via ATP hydrolysis into the proteolytic chamber formed by the ring structure and then finally cleave the substrate into large peptides (Wickner et al, 1999;Chandu and Nandi, 2004).…”

mentioning

confidence: 99%

“…To date, most organisms, both eukaryotic and prokaryotic, have been found to possess only a single form of Lon, which is located in mitochondria. However, plants have evolved four separate isoforms of Lon protease located in mitochondria, chloroplasts, and peroxisomes (Janska, 2005). The lon1 gene in plants was first identified in maize (Zea mays; Barakat et al, 1998) and shortly after ORF239, a protein associated with cytoplasmic male sterility in common bean (Phaseolus vulgaris), was identified as a target of Lon1 in plant mitochondria (Sarria et al, 1998).…”

mentioning

confidence: 99%

Loss of Lon1 in Arabidopsis Changes the Mitochondrial Proteome Leading to Altered Metabolite Profiles and Growth Retardation without an Accumulation of Oxidative Damage

Solheim

Hatzopoulos

et al. 2012

Plant Physiology

View full text Add to dashboard Cite

Lon1 is an ATP-dependent protease and chaperone located in the mitochondrial matrix in plants. Knockout in Arabidopsis (Arabidopsis thaliana) leads to a significant growth rate deficit in both roots and shoots and lowered activity of specific mitochondrial enzymes associated with respiratory metabolism. Analysis of the mitochondrial proteomes of two lon1 mutant alleles (lon1-1 and lon1-2) with different severities of phenotypes shows a common accumulation of several stress marker chaperones and lowered abundance of Complexes I, IV, and V of OXPHOS. Certain enzymes of the tricarboxylic acid (TCA) cycle are modified or accumulated, and TCA cycle bypasses were repressed rather than induced. While whole tissue respiratory rates were unaltered in roots and shoots, TCA cycle intermediate organic acids were depleted in leaf extracts in the day in lon1-1 and in both lon mutants at night. No significant evidence of broad steady-state oxidative damage to isolated mitochondrial samples could be found, but peptides from several specific proteins were more oxidized and selected functions were more debilitated in lon1-1. Collectively, the evidence suggests that loss of Lon1 significantly modifies respiratory function and plant performance by small but broad alterations in the mitochondrial proteome gained by subtly changing steady-state protein assembly, stability, and damage of a range of components that debilitate an anaplerotic role for mitochondria in cellular carbon metabolism.Functional proteins are assembled from polypeptides that have undergone many steps of folding and posttranslational modification. As such, many pitfalls exist where anomalous polypeptide species or configurations can form and affect biological functions. These aberrant proteins can result from errors during translation, misfolding of the nascent polypeptide, damage to the native proteins from oxidation events, or even incorrect stoichiometry of protein complex subunits (Adam, 2000;Schaller, 2004). In the cytosol, these aberrant molecules are largely removed via the 26S proteasome pathway, which involves ubiquitination of the protein substrate and subsequent degradation into peptides and eventually amino acids that can then be recycled (Hershko and Ciechanover, 1998). Oxidized cytosolic proteins are primarily degraded by the 20S core particle of the 26S proteasome in a ubiquitin-independent manner (Davies, 2001). However, these major proteasome pathways are not directly available to turnover proteins in intraorganellar environments. Therefore, mitochondria, chloroplasts, and peroxisomes possess alternate pathways governed by networks of chaperone and protease functions for the maintenance of protein homeostasis.The AAA + protease class (ATPases associated with diverse cellular activities) of proteases (Neuwald et al., 1999;Ogura and Wilkinson, 2001) are largely responsible for this organellar protein homeostasis in plants (Janska, 2005). The ATP-dependent proteases (including the Clp, FtsH, and Lon subclasses) are multimeric ring structures (Lupas e...

show abstract

“…Lon protease was first identified in Escherichia coli (58), and Lon-homologous proteins have been further identified in a wide range of living organisms, including not only eubacteria but also archaea (42), Saccharomyces cerevisiae (65)(66)(67), plants (3,34,51), and animals (7,68). Lon protease is an ATP-and Mg 2ϩ -dependent protease belonging to the superfamily of AAA ϩ proteins (ATPases associated with different cellular activities) (43,45).…”

mentioning

confidence: 99%

Lon Protease of Azorhizobium caulinodans ORS571 Is Required for Suppression of reb Gene Expression

Nakajima

Aono

Tsukada

et al. 2012

Appl Environ Microbiol

View full text Add to dashboard Cite

ABSTRACTBacterial Lon proteases play important roles in a variety of biological processes in addition to housekeeping functions. In this study, we focused on the Lon protease ofAzorhizobium caulinodans, which can fix nitrogen both during free-living growth and in stem nodules of the legumeSesbania rostrata. The nitrogen fixation activity of anA. caulinodanslonmutant in the free-living state was not significantly different from that of the wild-type strain. However, the stem nodules formed by thelonmutant showed little or no nitrogen fixation activity. By microscopic analyses, two kinds of host cells were observed in the stem nodules formed by thelonmutant. One type has shrunken host cells containing a high density of bacteria, and the other type has oval or elongated host cells containing a low density or no bacteria. This phenotype is similar to apraRmutant highly expressing therebgenes. Quantitative reverse transcription-PCR analyses revealed thatrebgenes were also highly expressed in thelonmutant. Furthermore, alon rebdouble mutant formed stem nodules showing higher nitrogen fixation activity than thelonmutant, and shrunken host cells were not observed in these stem nodules. These results suggest that Lon protease is required to suppress the expression of therebgenes and that high expression ofrebgenes in part causes aberrance in theA. caulinodans-S. rostratasymbiosis. In addition to the suppression ofrebgenes, it was found that Lon protease was involved in the regulation of exopolysaccharide production and autoagglutination of bacterial cells.

show abstract

ATP‐dependent proteases in plant mitochondria: What do we know about them today?

Cited by 33 publications

References 42 publications

Cost of Having the Largest Mitochondrial Genome: Evolutionary Mechanism of Plant Mitochondrial Genome

Cost of Having the Largest Mitochondrial Genome: Evolutionary Mechanism of Plant Mitochondrial Genome

Loss of Lon1 in Arabidopsis Changes the Mitochondrial Proteome Leading to Altered Metabolite Profiles and Growth Retardation without an Accumulation of Oxidative Damage

Lon Protease of Azorhizobium caulinodans ORS571 Is Required for Suppression of reb Gene Expression

Contact Info

Product

Resources

About