Proteomic and Bioinformatic Profiling of Transporters in Higher Plant Mitochondria

Abstract

To function as a metabolic hub, plant mitochondria have to exchange a wide variety of metabolic intermediates as well as inorganic ions with the cytosol. As identified by proteomic profiling or as predicted by MU-LOC, a newly developed bioinformatics tool, Arabidopsis thaliana mitochondria contain 128 or 143 different transporters, respectively. The largest group is the mitochondrial carrier family, which consists of symporters and antiporters catalyzing secondary active transport of organic acids, amino acids, and nucleotides across the inner mitochondrial membrane. An impressive 97% (58 out of 60) of all the known mitochondrial carrier family members in Arabidopsis have been experimentally identified in isolated mitochondria. In addition to many other secondary transporters, Arabidopsis mitochondria contain the ATP synthase transporters, the mitochondria protein translocase complexes (responsible for protein uptake across the outer and inner membrane), ATP-binding cassette (ABC) transporters, and a number of transporters and channels responsible for allowing water and inorganic ions to move across the inner membrane driven by their transmembrane electrochemical gradient. A few mitochondrial transporters are tissue-specific, development-specific, or stress-response specific, but this is a relatively unexplored area in proteomics that merits much more attention.

Dynamics and stabilization mechanism of mitochondrial cristae morphofunction associated with turgor-driven cardiolipin biosynthesis under salt stress conditions

“…There is accumulating evidence that an increase in K + and Ca 2+ influx play a crucial role in mitochondrial swelling 36 . Taken together with our data and the previous reports on the mitochondrial osmotic and hydraulic regulations 37 , 38 , the reversible V Mito changes could be attributed to the transient water inflow into the matrix through AQPs localized in IMM and permeability transition pores (PTPs) localized in the outer mitochondrial membrane (OMM) in mitochondria 39 , 40 , in accordance with the water potential gradient, presumably associated with enzymatic cascade reactions by the ion channels. Increases in IMM permeability might also be accompanied with the increase in Ca 2+ influx 41 .…”

Plant mitochondria – past, present and future

“…Movement of ions and small molecules across the IMM is strictly regulated by a wide array of transporters, which are therefore responsible for the metabolic interactions with the cytosol and mitochondrial metabolic and ionic homeostasis (Lee and Millar, 2016). As many as 200 transporters of different types have been identified in Arabidopsis mitochondria by proteomic and bioinformatic profiling (Møller et al, 2020b), including the TIM and TOM complexes (see Section 6.2) and the proton translocator subunits of the respiratory complexes (see Section 7).…”

“…The IMM also contains a number of ABC transporters (Møller et al, 2020b), one of which is responsible for the export of iron-sulfur centers synthesized in the matrix and needed elsewhere in the cell (Schaedler et al, 2014).…”

Versatile Roles of Aquaporins in Plant Growth and Development

“…Accordingly, changes in the activities of chloroplast envelope AQPs likely impact light signaling and plant growth. Some AQPs like AtTIP5;1 have been documented or predicted to be localized to the mitochondria in plants [ 126 , 188 ], yet it is unclear whether these AQPs transfer H 2 O 2 across the mitochondrial membrane. To date, no AQP has been detected in plant peroxisomes.…”