Pom1 kinase links division plane position to cell polarity by regulating Mid1p cortical distribution

Celton-Morizur S, Racine V, Sibarita JB, Paoletti A.
J Cell Sci.. 2006 Nov 15; 119(Pt 22): 4710-8
DOI: jcs.03261 [pii]10.1242/jcs.03261

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In fission yeast, Mid1p, a major determinant for division plane position, defines
a medial cortical compartment where it recruits myosin II at the onset of mitosis
to initiate contractile ring assembly. How Mid1p is restricted to the medial
cortex is unknown. We report here that in a pom1 polarity mutant, which displays
a monopolar growth pattern, Mid1p distribution expands towards the non-growing
cell tip, uncoupling Mid1p localization from nuclear position. This accounts for
the displacement of the contractile ring during mitosis. By contrast, Mid1p
localization is normal in a bud6Delta strain, indicating that Mid1p
misdistribution is not a general consequence of monopolar growth. We conclude
that Pom1 kinase acts as a negative regulator of Mid1p distribution, excluding
Mid1p from non-growing ends, whereas a Pom1-independent mechanism prevents Mid1p
association with growing ends. Our work therefore provides evidence that cell
polarity regulators influence the distribution of Mid1p, linking division plane
position to cell polarity.

DOI: 10.1242/jcs.03261
PMID: 17077120 [Indexed for MEDLINE]

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