Fig. 7. A model of negative regulation of Mid1p cortical distribution. In wild-type cells, Pom1 kinase (green) is delivered to the cell tips in a microtubule-dependent manner. Before NETO (top), Pom1p excludes Mid1p (red) from the non-growing tip while at the growing tip (blue arrow), other polarity factors (blue) may act in conjunction with Pom1p. These two mechanisms operate at the two growing tips after NETO (middle). This allows the formation of a medial cortical band of Mid1p in early phases of the cell cycle and yields to the formation of a centrally placed contractile ring during mitosis (bottom). In pom1-deficient cells, which have a monopolar pattern of growth, Mid1p is only excluded from the growing tips. Mid1p asymmetrical distribution is responsible for the displacement of the contractile ring towards the non-growing tip of the cell during mitosis. Microtubules (orange) are represented during interphase with their plus ends facing cell tips and their minus ends anchored on the nuclear envelope (black circle) and during mitosis (bottom) as they form an intranuclear mitotic spindle.