Published online January 28, 2008
doi:10.1083/jcb.200705049
The Journal of Cell Biology, Vol. 180, No. 2, 325-339
The Rockefeller University Press, 0021-9525 $30.00
© 2008 Liu et al.
Making two organelles from one: Woronin body biogenesis by peroxisomal protein sorting
Fangfang Liu,
Seng Kah Ng,
Yanfen Lu,
Wilson Low,
Julian Lai, and
Gregory Jedd
Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore 117604
Correspondence to Gregory Jedd: gregory{at}tll.org.sg
Woronin bodies (WBs) are dense-core organelles that are found exclusively in filamentous fungi and that seal the septal pore in response to wounding. These organelles consist of a membrane-bound protein matrix comprised of the HEX protein and, although they form from peroxisomes, their biogenesis is poorly understood. In Neurospora crassa, we identify Woronin sorting complex (WSC), a PMP22/MPV17-related membrane protein with dual functions in WB biogenesis. WSC localizes to large peroxisome membranes where it self-assembles into detergent-resistant oligomers that envelop HEX assemblies, producing asymmetrical nascent WBs. In a reaction requiring WSC, these structures are delivered to the cell cortex, which permits partitioning of the nascent WB and WB inheritance. Our findings suggest that WSC and HEX collaborate and control distinct aspects of WB biogenesis and that cortical association depends on WSC, which in turn depends on HEX. This dependency helps order events across the organellar membrane, permitting the peroxisome to produce a second organelle with a distinct composition and intracellular distribution.
Abbreviations used in this paper: BiFC, bimolecular fluorescence complementation; MDDS, mitochondrial DNA depletion syndrome; PTS1, peroxisome-targeting signal 1; WB, Woronin body; WSC, Woronin sorting complex.
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