Role of Misshappen (NIK/Msn) kinases and Extended-Synaptotagmins (E-Syts) in Wnt and FGF intracellular signaling pathways.

畸形 (NIK/Msn) 激酶和扩展突触结合蛋白 (E-Syts) 在 Wnt 和 FGF 细胞内信号传导通路中的作用。

• 批准号: RGPIN-2017-06128
• 负责人: Moss, Thomas
• 金额: $ 2.91万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712057
• 关键词: Role; Misshappen; NIK; Msn; kinases

Signalling between cells is fundamental to determining the metazoan body plan and in controlling growth and differentiation. Hence, a large number of families of signalling molecules and their cognate receptors have evolved to enable the complexities of early development, organogensis and homeostasis. Several of these families are of importance during early development, in particular the Wingless (Wnt) and Fibroblast Growth Factors (FGFs) families. These play separate, but interrelated, roles during development and act through distinct as well as shared transduction pathways. We have identified novel elements of the FGF and Wnt signalling pathways that provide potential windows into important aspects of signalling and inter-pathway crosstalk. We propose mechanistic studies that will provide new insight into the complex network of intracellular signalling. We were first to identify a role for the Extended Synaptotagmin 2 (ESyt2) in FGF signalling. The ESyts are a multi-C2-domain phospholipid-binding membrane protein, that function as endocytic adapters for the FGF Receptors (FGFRs). ESyt2 regulates the MAP-kinase pathway by mediating FGFR endocytosis, and plays probably related roles in endoplasmic reticulum - plasma membrane (ER-PM) junctioning, Store Operated Calcium Entry (SOCE)/Ca2+-signaling, and transport of phospholipids to the PM. To understand their physiological roles, we have generated ESyt1/2/3-null mice, established ESyt-null cell lines and shown them to have defects in Ca2+ signalling, and have begun genetic studies of the unique ESyt ortholog in Drosophila. We propose to use these tools to determine the in vitro and in vivo functions of the ESyts and how they impinge on phospholipid metabolism, and affect FGF and potentially Wnt signal transduction. Wnt signalling has been established as a key player in developmental patterning. However, despite considerable scientific effort, our understanding of crosstalk between the canonical beta-catenin, non-canonical Planar Cell Polarity and Ca2+ signalling pathways remains rudimentary. We recently discovered that the Xenopus Misshapen (Msn) homologs TNIK and MINK signalling kinases form integral components of both the canonical and non-canonical Wnt pathways. Our data strongly suggest the balance between the canonical and non-canonical pathways is controlled by proteolysis of TNIK and MINK, which determines both their kinase activities and subcellular locations. We have shown that this cleavage is conserved, since the unique Drosophila Msn is also cleaved during development. We propose a series of genetic, cell and molecular studies to determine the developmental and physiological significance of Msn cleavage, and hence to better understand the complex control of Wnt signalling.

细胞间的信号传递是决定后生动物体型和控制生长和分化的基础。因此，大量的信号分子家族及其同源受体已经进化，使早期发育、器官发生和动态平衡的复杂性成为可能。其中几个家族在早期发育过程中起重要作用，特别是无翼(WNT)和成纤维细胞生长因子(FGFs)家族。它们在发育过程中扮演着不同但又相互关联的角色，并通过不同的和共享的转导途径发挥作用。我们已经确定了成纤维细胞生长因子和Wnt信号通路的新元件，它们为了解信号和通路间串扰的重要方面提供了潜在的窗口。我们提出的机制研究将为细胞内信号传递的复杂网络提供新的见解。 我们首先确定了扩展突触素2(ESyt2)在成纤维细胞生长因子信号转导中的作用。ESyts是一种多C2结构域的磷脂结合膜蛋白，其功能是作为成纤维细胞生长因子受体(FGFRs)的内吞适配器。ESyt2通过介导FGFR内吞作用来调节MAP-K途径，并可能在内质网-质膜(ER-PM)连接、存储操作的钙内流(SOCE)/钙离子-信号转导以及磷脂向PM的运输中发挥作用为了了解它们的生理作用，我们培育了ESyt1/2/3缺失的小鼠，建立了ESyt缺失的细胞系，并证明它们在钙信号转导方面存在缺陷，并开始了对果蝇中独特的ESyt同源基因的遗传学研究。我们建议使用这些工具来确定ESyts的体外和体内功能，以及它们如何影响磷脂代谢，并影响成纤维细胞生长因子和潜在的Wnt信号转导。 WNT信号已被确定为发育模式中的关键角色。然而，尽管有相当多的科学努力，我们对典型的β-连环蛋白、非规范的平面细胞极性和钙信号通路之间的串扰的理解仍然处于初级水平。我们最近发现，非洲爪蛙畸形蛋白(MSN)同源物tnik和水貂信号通路构成了规范和非规范Wnt途径的组成部分。我们的数据有力地表明，规范和非规范途径之间的平衡是由tnik和mink的蛋白分解控制的，这决定了它们的激酶活性和亚细胞位置。我们已经证明了这种切割是保守的，因为独特的果蝇MSN在发育过程中也被切割。我们提出了一系列的遗传学、细胞和分子研究，以确定MSN裂解的发育和生理意义，从而更好地理解Wnt信号的复杂控制。