The chloroplast signal recognition particle (cpSRP) and its receptor, cpFtsY, posttranslationally target the nuclear-encoded light-harvesting chlorophyll-binding proteins (LHCPs) to the translocase Alb3 in the thylakoid membrane. In this study, we analyzed the interplay between the cpSRP pathway components, the substrate protein LHCP and the translocase Alb3 by using in vivo and in vitro techniques. We propose that cpSRP43 is crucial for the binding of LHCP-loaded cpSRP and cpFtsY to Alb3. In addition, our data suggest that a direct interaction between Alb3 and LHCP contributes to the formation of this complex.
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http://dx.doi.org/10.1016/j.febslet.2010.08.053 | DOI Listing |
J Mol Biol
March 2019
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA. Electronic address:
Different attributes of membrane protein substrates have been proposed and characterized as translocation-pathway determinants. However, several gaps in our understanding of the mechanism of targeting, insertion, and assembly of inner-membrane proteins exist. Specifically, the role played by hydrophilic N-terminal tails in pathway selection is unclear.
View Article and Find Full Text PDFPhotosynth Res
December 2018
Molecular Biology of Plant Organelles, Ruhr-University Bochum, Universitätsstraße 150, 44780, Bochum, Germany.
The light-harvesting chlorophyll a/b binding proteins (LHCP) belong to a large family of membrane proteins. They form the antenna complexes of photosystem I and II and function in light absorption and transfer of the excitation energy to the photosystems. As nuclear-encoded proteins, the LHCPs are imported into the chloroplast and further targeted to their final destination-the thylakoid membrane.
View Article and Find Full Text PDFBiophys J
September 2017
Institute of Microbiology and Molecular Biology, University of Hohenheim, Stuttgart, Germany. Electronic address:
The insertion of newly synthesized membrane proteins is a well-regulated and fascinating process occurring in every living cell. Several translocases and insertases have been found in prokaryotic and eukaryotic cells, the Sec61 complex and the Get complex in the endoplasmic reticulum and the SecYEG complex and YidC in bacteria and archaea. In mitochondria, TOM and TIM complexes transport nuclear-encoded proteins, whereas the Oxa1 is required for the insertion of mitochondria-encoded membrane proteins.
View Article and Find Full Text PDFPlant Physiol
April 2017
Horticultural Sciences Department and Plant Molecular and Cellular Biology, University of Florida, Gainesville, Florida 32611 (Y.L., J.R.M., G.A.A., K.C.); and
Most chloroplast proteins are synthesized in the cytosol and imported into chloroplasts. Many imported proteins are further targeted to the thylakoid membrane and lumen by the SEC1, TAT, or SRP/ALB3 translocases. Others are targeted to the inner chloroplast envelope membrane by undescribed translocases.
View Article and Find Full Text PDFJ Biol Chem
January 2017
From the Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
The universally conserved signal recognition particle (SRP) co-translationally delivers newly synthesized membrane and secretory proteins to the target cellular membrane. The only exception is found in the chloroplast of green plants, where the chloroplast SRP (cpSRP) post-translationally targets light-harvesting chlorophyll a/b-binding proteins (LHCP) to the thylakoid membrane. The mechanism and regulation of this post-translational mode of targeting by cpSRP remain unclear.
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