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International Journal of Cell Biology
Volume 2012, Article ID 657423, 11 pages
Research Article

PKC-Mediated ZYG1 Phosphorylation Induces Fusion of Myoblasts as well as of Dictyostelium Cells

1Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
2Zoologisch Institute, Ludwig-Maximilians Universitat, 80333 München, Germany
3Central Research Laboratory, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
4Department of Physiology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan

Received 12 June 2011; Revised 1 October 2011; Accepted 1 October 2011

Academic Editor: Andre Van Wijnen

Copyright © 2012 Aiko Amagai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We have previously demonstrated that a novel protein ZYG1 induces sexual cell fusion (zygote formation) of Dictyostelium cells. In the process of cell fusion, involvements of signal transduction pathways via Ca2+ and PKC (protein kinase C) have been suggested because zygote formation is greatly enhanced by PKC activators. In fact, there are several deduced sites phosphorylated by PKC in ZYG1 protein. Thereupon, we designed the present work to examine whether or not ZYG1 is actually phosphorylated by PKC and localized at the regions of cell-cell contacts where cell fusion occurs. These were ascertained, suggesting that ZYG1 might be the target protein for PKC. A humanized version of zyg1 cDNA (mzyg1) was introduced into myoblasts to know if ZYG1 is also effective in cell fusion of myoblasts. Quite interestingly, enforced expression of ZYG1 in myoblasts was found to induce markedly their cell fusion, thus strongly suggesting the existence of a common signaling pathway for cell fusion beyond the difference of species.