Open AccessTarget of Rapamycin and LST8 Proteins Associate with Membranes from the Endoplasmic Reticulum in the Unicellular Green Alga Chlamydomonas reinhardtii
Author(s) -
Sandra Díaz-Troya,
Francisco J. Florencio,
José L. Crespo
Publication year - 2008
Publication title -
eukaryotic cell
Language(s) - English
Resource type - Journals
eISSN - 1535-9778
pISSN - 1535-9786
DOI - 10.1128/ec.00361-07
Subject(s) - chlamydomonas reinhardtii , chlamydomonas , biology , endoplasmic reticulum , microbiology and biotechnology , biochemistry , cell fractionation , saccharomyces cerevisiae , yeast , mutant , membrane , gene
The highly conserved target of rapamycin (TOR) kinase is a central controller of cell growth in all eukaryotes. TOR exists in two functionally and structurally distinct complexes, termed TOR complex 1 (TORC1) and TORC2. LST8 is a TOR-interacting protein that is present in both TORC1 and TORC2. Here we report the identification and characterization of TOR and LST8 in large protein complexes in the model photosynthetic green algaChlamydomonas reinhardtii . We demonstrate thatChlamydomonas LST8 is part of a rapamycin-sensitive TOR complex in this green alga. Biochemical fractionation and indirect immunofluorescence microscopy studies indicate that TOR and LST8 exist in high-molecular-mass complexes that associate with microsomal membranes and are particularly abundant in the peri-basal body region inChlamydomonas cells. ASaccharomyces cerevisiae complementation assay demonstrates thatChlamydomonas LST8 is able to functionally and structurally replace endogenous yeast LST8 and allows us to propose that binding of LST8 to TOR is essential for cell growth.