Cyk3 acts in actomyosin ring independent cytokinesis by recruiting Inn1 to the yeast bud neck

• Published in: Molecular genetics and genomics : MGG Vol. 282; no. 4; pp. 437 - 451
• Main Authors: Jendretzki, Arne, Ciklic, Ivan, Rodicio, Rosaura, Schmitz, Hans-Peter, Heinisch, Jürgen J.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.10.2009; Springer Nature B.V
• Subjects: Actomyosin - metabolism; Actomyosin - physiology; Amino Acid Sequence; Animal Genetics and Genomics; Biochemistry; Biomedical and Life Sciences; Cell Cycle Proteins - metabolism; Cell division; Cytokinesis - genetics; Cytokinesis - physiology; Genomics; Human Genetics; Life Sciences; Microbial Genetics and Genomics; Microtubule-Associated Proteins - chemistry; Microtubule-Associated Proteins - genetics; Microtubule-Associated Proteins - metabolism; Microtubule-Associated Proteins - physiology; Molecular Sequence Data; Organisms, Genetically Modified; Original Paper; Phylogeny; Plant Genetics and Genomics; Plasma; Protein Binding; Protein Structure, Tertiary - physiology; Protein Transport; Proteins; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae - physiology; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Saccharomyces cerevisiae Proteins - physiology; Sequence Homology, Amino Acid; Tissue Distribution; Transfection; Yeast; Hof1; Iqg1; Actomyosin ring; Myo1; Inn1; Cytokinesis
• ISSN: 1617-4615; 1617-4623
• DOI: 10.1007/s00438-009-0476-0

Cytokinesis in yeast can be achieved by plasma membrane ingression, which is dependent on actomyosin ring constriction. Inn1 presumably couples these processes by interaction with both the plasma membrane and the temporary actomyosin ring component Hof1. In addition, an actomyosin ring independent cytokinesis pathway exists in yeast. We here identified Cyk3, a key component of the alternative pathway, as a novel interaction partner of Inn1. The carboxy-terminal proline rich part of Inn1 binds the SH3 domains of either Cyk3 or Hof1. Strains with truncated proteins lacking either of these SH3 domains do not display any severe phenotypes, but are synthetically lethal, demonstrating their crucial role in cytokinesis. Overexpression of CYK3 leads to an actomyosin ring independent recruitment of Inn1 to the bud neck, further supporting the significance of this interaction in vivo. Moreover, overexpression of CYK3 in a myo1 or an iqg1 deletion not only restores viability, but also the recruitment of Inn1 to the bud neck. We propose that Cyk3 is part of an actomyosin ring independent cytokinesis pathway, which acts as a rescue mechanism to recruit Inn1 to the bud neck.