|
|
|
|
|
|
|
||
J. Cell Biol.,
Volume 141, Number 2, April 20, 1998 385-395
Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
Results of in vitro and genetic studies have
provided evidence for four pathways by which proteins
are targeted to the chloroplast thylakoid membrane.
Although these pathways are initially engaged by distinct substrates and involve some distinct components,
an unresolved issue has been whether multiple pathways converge on a common translocation pore in the
membrane. A homologue of eubacterial SecY called
cpSecY is localized to the thylakoid membrane. Since SecY is a component of a protein-translocating pore in
bacteria, cpSecY likely plays an analogous role. To explore the role of cpSecY, we obtained maize mutants
with transposon insertions in the corresponding gene.
Null cpSecY mutants exhibit a severe loss of thylakoid
membrane, differing in this regard from mutants lacking cpSecA. Therefore, cpSecY function is not limited
to a translocation step downstream of cpSecA. The
phenotype of cpSecY mutants is also much more pleiotropic than that of double mutants in which both the
cpSecA- and 
pH-dependent thylakoid-targeting pathways are disrupted. Therefore, cpSecY function is
likely to extend beyond any role it might play in these
targeting pathways. CpSecY mutants also exhibit a defect in chloroplast translation, revealing a link between
chloroplast membrane biogenesis and chloroplast gene
expression.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
