DOI: 10.1083/jcb.139.7.1677. Analysis of the Interactions of Preproteins with the Import Machinery over the Course of Protein Import into Chloroplasts

Analysis of the Interactions of Preproteins with the Import Machinery over the Course of Protein Import into Chloroplasts

10.1083/jcb.139.7.1677

Crossref journal-article

Rockefeller University Press

The Journal of Cell Biology (291)

Abstract

We have investigated the interactions of two nuclear-encoded preproteins with the chloroplast protein import machinery at three stages in import using a label-transfer crosslinking approach. During energy-independent binding at the outer envelope membrane, preproteins interact with three known components of the outer membrane translocon complex, Toc34, Toc75, and Toc86. Although Toc75 and Toc86 are known to associate with preproteins during import, a role for Toc34 in preprotein binding previously had not been observed. The interaction of Toc34 with preproteins is regulated by the binding, but not hydrolysis of GTP. These data provide the first evidence for a direct role for Toc34 in import, and provide insights into the function of GTP as a regulator of preprotein recognition. Toc75 and Toc86 are the major targets of cross-linking upon insertion of preproteins across the outer envelope membrane, supporting the proposal that both proteins function in translocation at the outer membrane as well as preprotein recognition. The inner membrane proteins, Tic(21) and Tic22, and a previously unidentified protein of 14 kD are the major targets of crosslinking during the late stages in import. These data provide additional support for the roles of these components during protein translocation across the inner membrane. Our results suggest a defined sequence of molecular interactions that result in the transport of nuclear-encoded preproteins from the cytoplasm into the stroma of chloroplasts.

Bibliography

Kouranov, A., & Schnell, D. J. (1997). Analysis of the Interactions of Preproteins with the Import Machinery over the Course of Protein Import into Chloroplasts. The Journal of Cell Biology, 139(7), 1677â1685.

Authors 2

Andrei Kouranov (first)
Danny J. Schnell (additional)

References 23 Referenced 166

10.1146/annurev.cellbio.12.1.1 / Annu Rev Cell Dev Biol / Import and routing of nucleus-encoded chloroplast proteins by Cline (1996)
10.1104/pp.75.3.675 / Plant Physiol / Thermolysin is a suitable protease for probing the surface of intact pea chloroplasts by Cline (1984)
10.1016/S0021-9258(19)83678-5 / J Biol Chem / Precursors to two nuclear-encoded chloroplast proteins bind to the outer envelope membrane before being imported into chloroplasts by Cline (1985)
10.1104/pp.114.2.405 / Plant Physiol / Mechanism of protein transport across the chloroplast envelope by Fuks (1997)
10.1126/science.7801125 / Science / A receptor component of the chloroplast protein translocation machinery by Hirsch (1994)
10.1016/0076-6879(86)18082-7 / Methods Enzymol / Isolation and characterization of chloroplast envelope membranes by Keegstra (1986)
10.1073/pnas.93.15.7684 / Proc Natl Acad Sci USA / Interaction of the protein import and folding machineries in the chloroplast by Kessler (1996)
10.1126/science.7973656 / Science / Identification of two GTP-binding proteins in the chloroplast protein import machinery by Kessler (1994)
10.1002/j.1460-2075.1996.tb00797.x / EMBO (Eur Mol Biol Organ) J / Topology of IEP110, a component of the chloroplastic protein import machinery present in the inner envelope membrane by Lübeck (1996)
10.1111/j.1399-3054.1997.tb03454.x / Physiologia Plantarum / Protein import into chloroplasts by Lübeck (1997)
10.1083/jcb.134.2.315 / J Cell Biol / Two components of the chloroplast protein import apparatus, IAP86 and IAP75, interact with the transit sequence during the recognition and translocation of precursor proteins at the outer envelope by Ma (1996)
10.1093/emboj/16.5.935 / EMBO (Eur Mol Biol Organ) J / Stable association of chloroplastic precursors with protein-translocation complexes that contain proteins from both envelope membranes and a stromal Hsp100 molecular chaperone by Nielsen (1997)
10.1016/S0021-9258(18)48513-4 / J Biol Chem / The binding of precursor proteins to chloroplasts requires nucleoside triphosphates in the intermembrane space by Olsen (1992)
10.1016/S0021-9258(18)83489-5 / J Biol Chem / ATP is required for the binding of precursor proteins to chloroplasts by Olsen (1989)
10.1073/pnas.84.10.3288 / Proc Natl Acad Sci USA / Protein import in chloroplasts requires a chloroplast ATPase by Pain (1987)
{'key': '2023072207221607200_B16', 'first-page': '93', 'article-title': 'Envelope membrane proteins that interact with chloroplastic precursor proteins', 'volume': '6', 'author': 'Perry', 'year': '1994', 'journal-title': 'Plant Cell'} / Plant Cell / Envelope membrane proteins that interact with chloroplastic precursor proteins by Perry (1994)
10.1083/jcb.120.1.103 / J Cell Biol / Identification of intermediates in the pathway of protein import into chloroplasts and their localization to envelope contact sites by Schnell (1993)
10.1126/science.7973649 / Science / Isolation of components of the chloroplast protein import machinery by Schnell (1994)
10.1016/S0962-8924(97)01111-2 / Trends Cell Biol / A nomenclature for the protein import components of the chloroplast envelope by Schnell (1997)
10.1046/j.1365-313X.1995.7030401.x / Plant J / A constituent of the chloroplast import complex represents a new type of GTP-binding protein by Seedorf (1995)
10.1002/j.1460-2075.1995.tb07241.x / EMBO (Eur Mol Biol Organ) J / A component of the chloroplastic protein import apparatus is targeted to the outer envelope membrane via a novel pathway by Tranel (1995)
10.1111/j.1365-313X.1991.00149.x / Plant J / Characterization of the protein import apparatus in isolated outer envelopes of chloroplasts by Waegemann (1991)
10.1016/S0021-9258(18)31630-2 / J Biol Chem / Identification of chloroplast envelope proteins in close proximity to a partially translocated chimeric precursor protein by Wu (1994)

Dates

Type	When
Created	23 years, 1 month ago (July 26, 2002, 12:46 p.m.)
Deposited	2 years, 1 month ago (July 22, 2023, 3:22 a.m.)
Indexed	3 weeks, 1 day ago (Aug. 5, 2025, 8:44 a.m.)
Issued	27 years, 7 months ago (Dec. 29, 1997)
Published	27 years, 7 months ago (Dec. 29, 1997)
Published Online	27 years, 7 months ago (Dec. 29, 1997)
Published Print	27 years, 7 months ago (Dec. 29, 1997)

Funders 0

None

BibTeX

@article{Kouranov_1997, title={Analysis of the Interactions of Preproteins with the Import Machinery over the Course of Protein Import into Chloroplasts}, volume={139}, ISSN={1540-8140}, url={http://dx.doi.org/10.1083/jcb.139.7.1677}, DOI={10.1083/jcb.139.7.1677}, number={7}, journal={The Journal of Cell Biology}, publisher={Rockefeller University Press}, author={Kouranov, Andrei and Schnell, Danny J.}, year={1997}, month=dec, pages={1677–1685} }

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