scholarly journals Author response: Germ layer-specific regulation of cell polarity and adhesion gives insight into the evolution of mesoderm

Author(s):  
Miguel Salinas-Saavedra ◽  
Amber Q Rock ◽  
Mark Q Martindale
2017 ◽  
Author(s):  
Miguel Salinas-Saavedra ◽  
Amber Q. Rock ◽  
Mark Q Martindale

AbstractIn triploblastic animals, Par-proteins regulate cell-polarity and adherens junctions of both ectodermal and endodermal epithelia. But, in embryos of the diploblastic cnidarian Nematostella vectensis, Par-proteins are degraded in all cells in the bifunctional gastrodermal epithelium. Using immunohistochemistry, CRISPR/Cas9 mutagenesis, and overexpression of specific mRNAs, we describe the functional association between Par-proteins, ß-catenin, and snail transcription factor genes in N. vectensis embryos. We demonstrate that the aPKC/Par complex regulates the localization of ß-catenin in the ectoderm by stabilizing its role in cell-adhesion, and that endomesodermal epithelial cells are organized by a different cell-adhesion system than that of overlying ectoderm. We also show that ectopic expression of snail genes, which are expressed in mesodermal derivatives in bilaterians, are sufficient to downregulate Par-proteins and translocate ß-catenin from the junctions to the cytoplasm in ectodermal cells. These data provide molecular insight into the evolution of epithelial structure and distinct mesodermal tissue in metazoan embryos.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Miguel Salinas-Saavedra ◽  
Amber Q Rock ◽  
Mark Q Martindale

In triploblastic animals, Par-proteins regulate cell-polarity and adherens junctions of both ectodermal and endodermal epithelia. But, in embryos of the diploblastic cnidarian Nematostella vectensis, Par-proteins are degraded in all cells in the bifunctional gastrodermal epithelium. Using immunohistochemistry, CRISPR/Cas9 mutagenesis, and mRNA overexpression, we describe the functional association between Par-proteins, ß-catenin, and snail transcription factor genes in N. vectensis embryos. We demonstrate that the aPKC/Par complex regulates the localization of ß-catenin in the ectoderm by stabilizing its role in cell-adhesion, and that endomesodermal epithelial cells are organized by a different cell-adhesion system than overlying ectoderm. We also show that ectopic expression of snail genes, which are expressed in mesodermal derivatives in bilaterians, is sufficient to downregulate Par-proteins and translocate ß-catenin from the junctions to the cytoplasm in ectodermal cells. These data provide molecular insight into the evolution of epithelial structure and distinct cell behaviors in metazoan embryos.


Author(s):  
Wenxiu Ru ◽  
Xiaoyan Zhang ◽  
Binglin Yue ◽  
Ao Qi ◽  
Xuemei Shen ◽  
...  
Keyword(s):  

2014 ◽  
Vol 328 (2) ◽  
pp. 284-295 ◽  
Author(s):  
Michael Sebbagh ◽  
Jean-Paul Borg

2003 ◽  
Vol 14 (4) ◽  
pp. 1501-1516 ◽  
Author(s):  
April S. Goehring ◽  
David A. Mitchell ◽  
Amy Hin Yan Tong ◽  
Megan E. Keniry ◽  
Charles Boone ◽  
...  

The p21-activated kinases Ste20p and Cla4p carry out undefined functions that are essential for viability during budding inSaccharomyces cerevisiae. To gain insight into the roles of Ste20p, we have used a synthetic lethal mutant screen to identify additional genes that are required in the absence of Cla4p. Altogether, we identified 65 genes, including genes with roles in cell polarity, mitosis, and cell wall maintenance. Herein, we focus on a set that defines a function carried out by Bni1p and several of its interacting proteins. We found that Bni1p and a group of proteins that complex with Bni1p (Bud6p, Spa2p, and Pea2p) are essential in acla4Δ mutant background. Bni1p, Bud6p, Spa2, and Pea2p are members of a group of polarity determining proteins referred to as the polarisome. Loss of polarisome proteins from acla4Δ strain causes cells to form elongated buds that have mislocalized septin rings. In contrast, other proteins that interact with or functionally associate with Bni1p and have roles in nuclear migration and cytokinesis, including Num1p and Hof1p, are not essential in the absence of Cla4p. Finally, we have found that Bni1p is phosphorylated in vivo, and a substantial portion of this phosphorylation is dependent on STE20. Together, these results suggest that one function of Ste20p may be to activate the polarisome complex by phosphorylation of Bni1p.


2005 ◽  
Vol 16 (10) ◽  
pp. 4595-4608 ◽  
Author(s):  
Judy L. Shih ◽  
Samara L. Reck-Peterson ◽  
Rick Newitt ◽  
Mark S. Mooseker ◽  
Ruedi Aebersold ◽  
...  

Spa2p is a nonessential protein that regulates yeast cell polarity. It localizes early to the presumptive bud site and remains at sites of growth throughout the cell cycle. To understand how Spa2p localization is regulated and to gain insight into its molecular function in cell polarity, we used a coimmunoprecipitation strategy followed by tandem mass spectrometry analysis to identify proteins that associate with Spa2p in vivo. We identified Myo1p, Myo2p, Pan1p, and the protein encoded by YFR016c as proteins that interact with Spa2p. Strikingly, all of these proteins are involved in cell polarity and/or actin function. Here we focus on the functional significance of the interactions of Spa2p with Myo2p and Myo1p. We find that localization of Spa2GFP to sites of polarized growth depends on functional Myo2p but not on Myo1p. We also find that Spa2p, like Myo2p, cosediments with F-actin in an ATP-sensitive manner. We hypothesize that Spa2p associates with actin via a direct or indirect interaction with Myo2p and that Spa2p may be involved in mediating polarized localization of polarity proteins via Myo2p. In addition, we observe an enhanced cell-separation defect in a myo1spa2 strain at 37°C. This provides further evidence that Spa2p is involved in cytokinesis and cell wall morphogenesis.


2009 ◽  
Vol 126 ◽  
pp. S256 ◽  
Author(s):  
Masaki Takeuchi ◽  
Maiko Takahashi ◽  
Shinichi Aizawa

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