Localization of Type I Myosin and F-actin to the Leading Edge Region of the Forespore Membrane in Schizosaccharomyces pombe

Cell Structure and Function

Chikashi Shimoda¹  Taro Nakamura¹  Akiko Itadani¹ 

[1] Department of Biology, Graduate School of Science, Osaka City University

关键词: calmodulin;    F-actin;    forespore membrane;    leading edge;    myosin-I;   

DOI  :  10.1247/csf.06027

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(45)Cited-By(4)Myo1, a heavy chain of type I myosin of the fission yeast Schizosaccharomyces pombe, is essential for sporulation. Here we have analyzed the expression, localization and cellular function of the type I myosin light chain calmodulin, Cam2, encoded by cam2+. Transcription of cam2+ was constitutive and markedly enhanced in meiosis. The cam2 null mutant was viable and completed sporulation normally at 28°C, but formed four-spored asci poorly at 34°C. In those sporulation-defective cells, the forespore membrane was formed abnormally. A Cam2-GFP fusion protein accumulated at the cell poles in interphase cells and at the medial septation site in postmitotic cells, colocalizing with Myo1 and F-actin patches. During the mating process, a single Cam2-GFP dot was detected at the tip of the mating projection. During meiosis-I, the Cam2-GFP dots dispersed into the cell periphery and the cytoplasm. At metaphase-II, intense Cam2-GFP signals appeared near Meu14 rings which were formed at the leading edge of expanding forespore membranes. This localization of Cam2 was dependent upon Myo1; and sporulation defect of cam2Δ at 34°C was alleviated by overexpressing Myo1ΔIQ. These results suggest a close relationship between Cam2 and Myo1. In addition, both F-actin and Myo1 localized with Cam2 in the leading edge region. In summary, type I myosin and F-actin accumulate at the leading edge area of the forespore membrane and may play a pivotal role in its assembly.

【 授权许可】

Unknown