Tyrosine Kinase Signaling in Nuclear Morphodynamics

真核细胞，包括人类细胞，被分成被称为细胞器的隔间，这些隔间已经进化到执行特殊功能，同时保护细胞的其余部分免受潜在有害活动的影响。细胞器的分裂给细胞活动的协调带来了巨大的挑战。为了应对环境的变化或内部的变化，细胞必须重新排列其细胞器的结构和位置，以协调其整体形状的变化。细胞核是细胞中最大的细胞器，在保护和控制遗传信息方面发挥着至关重要的作用。然而，像其他细胞器一样，细胞核是高度动态的，它在细胞内的形状和位置会发生显著的变化。这些变化被认为对组织内细胞的正常功能产生深远的影响，从而影响组织的完整性。这些所谓的核形态动力学使细胞能够适应不断变化的条件，并在胚胎发育或成人组织修复等关键过程中表现出适当的行为。当细胞不能正确控制细胞核的形状和位置时，就会产生灾难性的生物学后果。事实上，核结构和定位的缺陷与癌症和退行性肌肉疾病等致命人类疾病的发展有关。然而，我们仍然不明白细胞是如何在分子水平上被指示重新排列细胞核的结构和位置的，这使得很难弄清楚这一过程如何在人类疾病中被解除管制。

Eukaryotic cells, including human cells, are divided into compartments called organelles that have evolved to perform specialized functions while protecting the rest of the cell from potentially harmful activities. This partition into organelles presents cells with big challenges in terms of coordination of cellular activities. In response to changes in the environment or to internal alterations, cells must rearrange the structure and positioning of their organelles in a manner that is coordinated with changes of their overall shape. The nucleus, the biggest organelle of a cell, is well known for its crucial function in protecting and controlling the genetic information. Like any other organelles, however, the nucleus is highly dynamic and undergoes remarkable changes in its shape and position within a cell. Such changes are believed to have profound impacts on the proper functioning of cells within tissues, hence on tissue integrity. These so-called nuclear morphodynamics enable cells to adapt to changing conditions and to exhibit an adequate behavior during key processes such as during embryonic development or during tissue repair in adult. When cells fail to correctly control the shape and position of their nucleus, this can have disastrous biological consequences. Indeed, defects in nuclear structure and positioning are correlated with the development of fatal human diseases like cancer and degenerative muscle diseases. However, we still do not understand how a cell is instructed, at the molecular level, to rearrange the structure and position of the nucleus, making it difficult to figure how this process might be deregulated in human diseases. To receive and relay instructions by extra- and intracellular signaling, cells possess sophisticated signaling devices in all organelles including the nucleus. The signaling circuits are composed of protein hardware that conveys signals through reversible protein modifications, including protein phosphorylation. Protein kinases, the enzymes that catalyze protein phosphorylation, act as molecular switches to transduce signals. Most of our knowledge regarding signaling mechanisms is limited to the initial signal reception and integration at the plasma membrane and signaling within the nucleus is not understood. The general objective of this program is to understand how protein phosphorylation generated within the nucleus can impact on the regulation of nuclear shape and positioning, and under which physiological and pathological conditions. Specifically, we will investigate a potential role for an important tyrosine kinase called Src, which can move to the nucleus in response to a variety of signals that alter the shape of a cell, and for a newly identified protein target of Src that resides in the nucleus. This fundamental work should contribute to a better foundation knowledge of diseases like cancer and degenerative diseases.