Temporal Control of Contractile Ring Assembly by Plo1 Regulation of Myosin II Recruitment by Mid1/Anillin

• Published in: Current biology Vol. 21; no. 6; pp. 473 - 479
• Main Authors: Almonacid, Maria, Celton-Morizur, Séverine, Jakubowski, Jennifer L., Dingli, Florent, Loew, Damarys, Mayeux, Adeline, Chen, Jun-Song, Gould, Kathleen L., Clifford, Dawn M., Paoletti, Anne
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 22.03.2011; Elsevier
• Subjects: Actomyosin - metabolism; Actomyosin - physiology; Binding Sites - genetics; CDC2 Protein Kinase - metabolism; Contractile Proteins - metabolism; Cytokinesis - physiology; Immunoprecipitation; Life Sciences; Mass Spectrometry; Microscopy, Fluorescence; Myosin Type II - metabolism; Phosphorylation; Plasmids - genetics; Protein Serine-Threonine Kinases - metabolism; Schizosaccharomyces - physiology; Schizosaccharomyces pombe; Schizosaccharomyces pombe Proteins - genetics; Schizosaccharomyces pombe Proteins - metabolism; Time-Lapse Imaging
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2011.02.003

In eukaryotes, cytokinesis generally involves an actomyosin ring, the contraction of which promotes daughter cell segregation. Assembly of the contractile ring is tightly controlled in space and time [1–4]. In the fission yeast, contractile ring components are first organized by the anillin-like protein Mid1 into medial cortical nodes [5–9]. These nodes then coalesce laterally into a functional contractile ring [10–13]. Although Mid1 is present at the medial cortex throughout G2 [14], recruitment of contractile ring components to nodes starts only at mitotic onset [12], indicating that this event is cell-cycle regulated. Polo kinases are key temporal coordinators of mitosis and cytokinesis [1], and the Polo-like kinase Plo1 is known to activate Mid1 nuclear export at mitotic onset [15, 16], coupling division plane specification to nuclear position [7]. Here we provide evidence that Plo1 also triggers the recruitment of contractile ring components into medial cortical nodes. Plo1 binds at least two independent sites on Mid1, including a consensus site phosphorylated by Cdc2. Plo1 phosphorylates several residues within the first 100 amino acids of Mid1, which directly interact with the IQGAP Rng2 [17], and influences the timing of myosin II recruitment. Plo1 thereby facilitates contractile ring assembly at mitotic onset. ▸ Mid1 has at least two Plo1 binding sites, and the interaction is favored by Cdc2 ▸ Plo1 phosphorylates multiple residues within the first 100 residues of Mid1 ▸ Phosphorylation of Mid1 1–100 by Plo1 modulates the timing of myosin II recruitment ▸ Mid1 1–100 interacts with a Rng2 fragment