Phosphatidylserine and GTPase activation control Cdc42 nanoclustering to counter dissipative diffusion

The anisotropic organization of plasma membrane constituents is indicative of mechanisms that drive the membrane away from equilibrium. However, defining these mechanisms is challenging due to the short spatiotemporal scales at which diffusion operates. Here, we use high-density single protein track...

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Bibliographic Details
Published in:Molecular biology of the cell 2018-06, Vol.29 (11), p.1299-1310
Main Authors: Sartorel, Elodie, Ünlü, Caner, Jose, Mini, Massoni-Laporte, Aurélie, Meca, Julien, Sibarita, Jean-Baptiste, McCusker, Derek
Format: Article
Language:English
Subjects:
Biochemistry, Molecular Biology
Brief Reports
Cellular Biology
Engineering Sciences
Life Sciences
Molecular biology
Signal and Image processing
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Summary:The anisotropic organization of plasma membrane constituents is indicative of mechanisms that drive the membrane away from equilibrium. However, defining these mechanisms is challenging due to the short spatiotemporal scales at which diffusion operates. Here, we use high-density single protein tracking combined with photoactivation localization microscopy (sptPALM) to monitor Cdc42 in budding yeast, a system in which Cdc42 exhibits anisotropic organization. Cdc42 exhibited reduced mobility at the cell pole, where it was organized in nanoclusters. The Cdc42 nanoclusters were larger at the cell pole than those observed elsewhere in the cell. These features were exacerbated in cells expressing Cdc42-GTP, and were dependent on the scaffold Bem1, which contributed to the range of mobility and nanocluster size exhibited by Cdc42. The lipid environment, in particular phosphatidylserine levels, also played a role in regulating Cdc42 nanoclustering. These studies reveal how the mobility of a Rho GTPase is controlled to counter the depletive effects of diffusion, thus stabilizing Cdc42 on the plasma membrane and sustaining cell polarity.
ISSN:1059-1524
1939-4586
DOI:10.1091/mbc.E18-01-0051