Cation selectivity of the presequence translocase channel Tim23 is crucial for efficient protein import

Denkert, Niels; Schendzielorz, Alexander Benjamin; Barbot, Mariam; Versemann, Lennart; Richter, Frank; Rehling, Peter; Meinecke, Michael

doi:10.7554/elife.28324

Cited by 38 publications

(26 citation statements)

References 42 publications

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“…S3). It will be interesting to see in future studies how exactly OPDA is passing the channel and if different routes for different charged molecules exist, as has been suggested for other relatively wide pores (30,31).…”

Section: The Expression Of Ja-responsive Genes Is Not Activated In Thmentioning

confidence: 97%

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JASSY, a chloroplast outer membrane protein required for jasmonate biosynthesis

Guan

Denkert

Eisa

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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Jasmonates are vital plant hormones that not only act in the stress response to biotic and abiotic influences, such as wounding, pathogen attack, and cold acclimation, but also drive developmental processes in cooperation with other plant hormones. The biogenesis of jasmonates starts in the chloroplast, where several enzymatic steps produce the jasmonate precursor 12-oxophytodienoic acid (OPDA) from α-linolenic acid. OPDA in turn is exported into the cytosol for further conversion into active jasmonates, which subsequently induces the expression of multiple genes in the nucleus. Despite its obvious importance, the export of OPDA across the chloroplast membranes has remained elusive. In this study, we characterized a protein residing in the chloroplast outer membrane, JASSY, which has proven indispensable for the export of OPDA from the chloroplast. We provide evidence that JASSY has channel-like properties and propose that it thereby facilitates OPDA transport. Consequently, a lack of JASSY in Arabidopsis leads to a deficiency in accumulation of jasmonic acids, which results in impaired expression of jasmonate target genes on exposure to various stresses. This results in plants that are more susceptible to pathogen attack and also exhibit defects in cold acclimation. jasmonate | plant hormones | chloroplast | membrane pore | cold acclimation Author contributions: J.S.

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Section: The Expression Of Ja-responsive Genes Is Not Activated In Thmentioning

confidence: 97%

“…The signal was digitized by a Digidata 1440a A/D converter and recorded with AxoScope 10.3 and Clampex 10.3 software (Molecular Devices). Automated data analysis was performed as described previously (30).…”

Section: Agrobacterium-mediated Transient Expression Of Fluorescent Pmentioning

confidence: 99%

JASSY, a chloroplast outer membrane protein required for jasmonate biosynthesis

Guan

Denkert

Eisa

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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“…Large unilamellar vesicles were prepared as described before 31,32 . Briefly, L-αphosphatidylcholin (PC), L-α-phosphatidylethanolamine (PE), L-α-phosphatidylserine (PS) and L-α-Phosphatidylinositol-4,5-bisphosphate (PIP2) were obtained from Avanti Polar Lipids (Alabaster, AL).…”

Section: Visualization Of Luv Deformation By Electron Microscopymentioning

confidence: 99%

Cooperativity of membrane-protein and protein-protein interactions control membrane remodeling by epsin 1 and regulate clathrin-mediated endocytosis

Meinecke

Kroppen

Teske

et al. 2020

Preprint

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Membrane remodeling is a critical process for many membrane trafficking events, including clathrin-mediated endocytosis. Several molecular mechanisms for protein induced membrane curvature have been described in some detail. Contrary, the effect that the physico-chemical properties of the membrane has on these processes is far less well understood. Here, we show that the membrane binding and curvature-inducing ENTH domain of epsin1 is regulated by phosphatidylserine (PS). ENTH binds to membranes in a PI(4,5)P2-dependent manner but only induces curvature in the presence of PS. On PS-containing membranes, the ENTH domain forms rigid homo-oligomers and assembles into clusters. Membrane binding and membrane remodeling can be separated by structure-to-function mutants. Such oligomerization mutants bind to membranes but do not show membrane remodeling activity. In vivo they are not able to rescue defects in epidermal growth factor receptor (EGFR) endocytosis in epsin knock-down cells. Together, these data show that the membrane lipid composition is important for the regulation of protein-dependent membrane deformation during clathrin-mediated endocytosis.

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“…A prime candidate for this would be the TIM23 complex, which imports proteins into the acidic and negatively charged mitochondrial matrix. While a structure of the TIM23 complex remains to be determined, and many aspects of its function are unclear, transport is known to use ∆ψ 7 , and the channel through the mitochondrial inner membrane has been shown to be selective against negative charges 34 .…”

Section: The Proton Ratchet May Be Reversed For Mitochondrial Proteinmentioning

confidence: 99%

Rate-limiting transport of positive charges through the Sec-machinery is integral to the mechanism of protein transport

Allen

Corey

Watkins

et al. 2019

Preprint

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The proton-motive force (PMF) -the electrochemical gradient of protons across energyconserving membranes -powers protein transport in bacteria, mitochondria and chloroplasts.Here, we propose a 'proton ratchet' mechanism for this process. In the Sec system of bacteria, protons are stripped from lysine side chains of the pre-protein at the cytosolic face of the plasma membrane, then replaced on the exterior, aided by the pH component of the PMF (∆pH; acidic outside). This gives the translocating region of pre-protein a net negative charge, promoting electrophoretic diffusion across the membrane driven by membrane-potential (∆ψ; positive outside). For mitochondrial import (through the TIM23 complex) the proton ratchet acts in the opposite direction, with negatively charged residues protonated for passage across the inner membrane into the negative matrix. The proton ratchet is an elegant solution for coupling the PMF to transport, likely to be used by a range of other transporters of charged molecules.

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Cation selectivity of the presequence translocase channel Tim23 is crucial for efficient protein import

Cited by 38 publications

References 42 publications

JASSY, a chloroplast outer membrane protein required for jasmonate biosynthesis

JASSY, a chloroplast outer membrane protein required for jasmonate biosynthesis

Cooperativity of membrane-protein and protein-protein interactions control membrane remodeling by epsin 1 and regulate clathrin-mediated endocytosis

Rate-limiting transport of positive charges through the Sec-machinery is integral to the mechanism of protein transport

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