Gene Symbol: TOC34
Description: translocon at the outer envelope membrane of chloroplasts 34
Alias: ARABIDOPSIS THALIANA TRANSLOCON AT THE OUTER ENVELOPE MEMBRANE OF CHLOROPLASTS 34, ATTOC34, MUG13.14, MUG13_14, OEP34, translocon at the outer envelope membrane of chloroplasts 34, translocon at the outer envelope membrane of chloroplasts 34
Species: thale cress

Top Publications

  1. Jarvis P, Chen L, Li H, Peto C, Fankhauser C, Chory J. An Arabidopsis mutant defective in the plastid general protein import apparatus. Science. 1998;282:100-3 pubmed
    ..The functional similarity of Toc33 to another translocon component (Toc34) implies that multiple different translocon complexes are present in plastids...
  2. Wallas T, Smith M, Sanchez Nieto S, Schnell D. The roles of toc34 and toc75 in targeting the toc159 preprotein receptor to chloroplasts. J Biol Chem. 2003;278:44289-97 pubmed
    ..The core of the Toc complex is composed of two receptor GTPases, Toc159 and Toc34, as well as Toc75, a beta-barrel membrane channel...
  3. Becker T, Jelic M, Vojta A, Radunz A, Soll J, Schleiff E. Preprotein recognition by the Toc complex. EMBO J. 2004;23:520-30 pubmed
    The Toc core complex consists of the pore-forming Toc75 and the GTPases Toc159 and Toc34. We confirm that the receptor form of Toc159 is integrated into the membrane...
  4. Bae W, Lee Y, Kim D, Lee J, Kim S, Sohn E, et al. AKR2A-mediated import of chloroplast outer membrane proteins is essential for chloroplast biogenesis. Nat Cell Biol. 2008;10:220-7 pubmed publisher
    ..Thus, AKR2A functions as a cytosolic mediator for sorting and targeting of nascent chloroplast OEM proteins to the chloroplast. ..
  5. von Loeffelholz O, Kriechbaumer V, Ewan R, Jonczyk R, Lehmann S, Young J, et al. OEP61 is a chaperone receptor at the plastid outer envelope. Biochem J. 2011;438:143-53 pubmed publisher
    ..We therefore propose that OEP61 is a novel chaperone receptor at the chloroplast outer envelope, mediating Hsp70-dependent protein targeting to chloroplasts. ..
  6. Reddick L, Vaughn M, Wright S, Campbell I, Bruce B. In vitro comparative kinetic analysis of the chloroplast Toc GTPases. J Biol Chem. 2007;282:11410-26 pubmed
    ..Here we present the first systematic kinetic characterization of four Toc GTPases (cytosolic domains of atToc33, atToc34, psToc34, and the GTPase domain of atToc159) to permit their direct comparison...
  7. Koenig P, Oreb M, Rippe K, Muhle Goll C, Sinning I, Schleiff E, et al. On the significance of Toc-GTPase homodimers. J Biol Chem. 2008;283:23104-12 pubmed publisher
  8. Li H, Chen L. A novel chloroplastic outer membrane-targeting signal that functions at both termini of passenger polypeptides. J Biol Chem. 1997;272:10968-74 pubmed
    ..One of the components, OEP34, is an outer membrane protein and is synthesized at its mature size in the cytosol without a distinguishable ..
  9. Lee J, Wang F, Schnell D. Toc receptor dimerization participates in the initiation of membrane translocation during protein import into chloroplasts. J Biol Chem. 2009;284:31130-41 pubmed publisher
    ..of the transit peptide of preproteins by the coordinate activities of two homologous GTPase Toc receptors, Toc34 and Toc159...

More Information


  1. Gutensohn M, Schulz B, Nicolay P, Flügge U. Functional analysis of the two Arabidopsis homologues of Toc34, a component of the chloroplast protein import apparatus. Plant J. 2000;23:771-83 pubmed
    Two Arabidopsis Toc34 homologues, atToc34 and atToc33, components of the chloroplast protein import machinery located in the outer envelope membrane, were recently isolated...
  2. Ling Q, Huang W, Baldwin A, Jarvis P. Chloroplast biogenesis is regulated by direct action of the ubiquitin-proteasome system. Science. 2012;338:655-9 pubmed publisher
    ..Thus, the ubiquitin-proteasome system acts on plastids to control their development. ..
  3. Oreb M, Höfle A, Mirus O, Schleiff E. Phosphorylation regulates the assembly of chloroplast import machinery. J Exp Bot. 2008;59:2309-16 pubmed publisher
    ..Two receptor components of this complex, Toc34 and Toc159, are GTPases, which can be phosphorylated by kinases present in the hosting membrane...
  4. Bauer J, Chen K, Hiltbunner A, Wehrli E, Eugster M, Schnell D, et al. The major protein import receptor of plastids is essential for chloroplast biogenesis. Nature. 2000;403:203-7 pubmed
    ..The Toc complex in the pea consists of three major components, Toc75, Toc34 and Toc159 (formerly termed Toc86)...
  5. Hust B, Gutensohn M. Deletion of core components of the plastid protein import machinery causes differential arrest of embryo development in Arabidopsis thaliana. Plant Biol (Stuttg). 2006;8:18-30 pubmed
    ..In contrast, despite the complete or almost complete lack of the import receptors Toc34 and Toc159, embryo development in the a tToc33/34 and atToc132/159 mutants proceeded slowly and was arrested later ..
  6. Shen G, Kuppu S, Venkataramani S, Wang J, Yan J, Qiu X, et al. ANKYRIN REPEAT-CONTAINING PROTEIN 2A is an essential molecular chaperone for peroxisomal membrane-bound ASCORBATE PEROXIDASE3 in Arabidopsis. Plant Cell. 2010;22:811-31 pubmed publisher
    ..The pleiotropic phenotype of akr2a mutants indicates that AKR2A plays many important roles in plant cellular metabolism and is essential for plant growth and development. ..
  7. Tsai L, Tu S, Li H. Insertion of atToc34 into the chloroplastic outer membrane is assisted by at least two proteinaceous components in the import system. J Biol Chem. 1999;274:18735-40 pubmed
    ..Using an Arabidopsis homologue of pea Toc34, atToc34, we show that the insertion of atToc34 was greatly reduced by thermolysin pretreatment of chloroplasts as assayed ..
  8. Koenig P, Oreb M, Höfle A, Kaltofen S, Rippe K, Sinning I, et al. The GTPase cycle of the chloroplast import receptors Toc33/Toc34: implications from monomeric and dimeric structures. Structure. 2008;16:585-96 pubmed publisher
    ..that dimerization is independent of nucleotide loading state, based on crystal structures of dimeric Pisum sativum Toc34 and monomeric Arabidopsis thaliana Toc33...