TY  - JOUR
A1  - Oreb, Igor-Mislav
A1  - Höfle, Anja
A1  - Mirus, Oliver
A1  - Schleiff, Enrico
T1  - Phosphorylation regulates the assembly of chloroplast import machinery
T2  - The journal of experimental botany
N2  - Chloroplast function depends on the translocation of cytosolically synthesized precursor proteins into the organelle. The recognition and transfer of most precursor proteins across the outer membrane depend on a membrane inserted complex. Two receptor components of this complex, Toc34 and Toc159, are GTPases, which can be phosphorylated by kinases present in the hosting membrane. However, the physiological function of phosphorylation is not yet understood in detail. It is demonstrated that both receptors are phosphorylated within their G-domains. In vitro, the phosphorylation of Toc34 disrupts both homo- and heterodimerization of the G-domains as determined using a phospho-mimicking mutant. In endogenous membranes this mutation or phosphorylation of the wild-type receptor disturbs the association of Toc34, but not of Toc159 with the translocation pore. Therefore, phosphorylation serves as an inhibitor for the association of Toc34 with other components of the complex and phosphorylation can now be discussed as a mechanism to exchange different isoforms of Toc34 within this ensemble.
KW  - GTPase
KW  - membrane complex dynamics
KW  - phosphorylation
KW  - plastids
KW  - protein complex assembly
KW  - protein translocation
KW  - TOC
Y1  - 2008
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/5852
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30-57952
SN  - 1460-2431
SN  - 0022-0957
N1  - ª 2008 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
VL  - 59
IS  - 9
SP  - 2309
EP  - 2316
PB  - Oxford University Press
CY  - Oxford
ER  -