The origins of the mesenchymal cells participating in tissue repair and pathological processes, notably tissue fibrosis, tumor invasiveness, and metastasis, are poorly understood. However, emerging evidence suggests that epithelial-mesenchymal transitions (EMTs) represent one important source of these cells. As we discuss here, processes similar to the EMTs associated with embryo implantation, embryogenesis, and organ development are appropriated and subverted by chronically inflamed tissues and neoplasias. The identification of the signaling pathways that lead to activation of EMT programs during these disease processes is providing new insights into the plasticity of cellular phenotypes and possible therapeutic interventions.

/pdf/the-basics-of-epithelial-mesenchymal-transition-xe9crzoewf.pdf

The basics of epithelial-mesenchymal transition

https://www.auburn.edu/academic/classes/biol/6190/refs/L04/1-s2.0-S0092867402009716-main.pdf

Integrins: Bidirectional, Allosteric Signaling Machines

Without epithelial–mesenchymal transitions, in which polarized epithelial cells are converted into motile cells, multicellular organisms would be incapable of getting past the blastula stage of embryonic development. However, this important developmental programme has a more sinister role in tumour progression. Epithelial–mesenchymal transition provides a new basis for understanding the progression of carcinoma towards dedifferentiated and more malignant states.

Epithelial–mesenchymal transitions in tumour progression

Epithelial-mesenchymal transition is an indispensable mechanism during morphogenesis, as without mesenchymal cells, tissues and organs will never be formed. However, epithelial-cell plasticity, coupled to the transient or permanent formation of mesenchyme, goes far beyond the problem of cell-lineage segregation. Understanding how mesenchymal cells arise from an epithelial default status will also have a strong impact in unravelling the mechanisms that control fibrosis and cancer progression.

Complex networks orchestrate epithelial–mesenchymal transitions

https://www.cell.com/cell/pdf/S0092-8674(00)81279-9.pdf

Cell Adhesion: The Molecular Basis of Tissue Architecture and Morphogenesis

Breaking the Integrin Hinge A DEFINED STRUCTURAL CONSTRAINT REGULATES INTEGRIN SIGNALING

How intracellular cytoskeletal and signaling proteins connect and communicate with the extracellular matrix (ECM) is a fundamental question in cell biology. Recent biochemical, cell biological, and genetic studies have revealed important roles of cytoplasmic integrin-linked kinase (ILK) and its interactive proteins in these processes. Cell adhesion to ECM is an important process that controls cell shape change, migration, proliferation, survival, and differentiation. Upon adhesion to ECM, integrins and a selective group of cytoskeletal and signaling proteins are recruited to cell matrix contact sites where they link the actin cytoskeleton to the ECM and mediate signal transduction between the intracellular and extracellular compartments. In this review, we discuss the molecular activities and cellular functions of ILK, a protein that is emerging as a key component of the cell–ECM adhesion structures.

/pdf/integrin-linked-kinase-ilk-and-its-interactors-a-new-5t8knqkm6v.pdf

Integrin-linked kinase (ILK) and its interactors: a new paradigm for the coupling of extracellular matrix to actin cytoskeleton and signaling complexes

Migfilin and Mig-2 link focal adhesions to filamin and the actin cytoskeleton and function in cell shape modulation.

Integrin activation is essential for dynamically linking the extracellular environment and cytoskeletal/signaling networks. Activation is controlled by integrins' short cytoplasmic tails (CTs). It is widely accepted that the head domain of talin (talin-H) can mediate integrin activation by binding to two sites in integrin β's CT; in integrin β3 this is an NPLY747 motif and the membrane-proximal region. Here, we show that the C-terminal region of integrin β3 CT, composed of a conserved TS752T region and NITY759 motif, supports integrin activation by binding to a cytosolic binding partner, kindlin-2, a widely distributed PTB domain protein. Co-transfection of kindlin-2 with talin-H results in a synergistic enhancement of integrin αIIbβ3 activation. Furthermore, siRNA knockdown of endogenous kindlin-2 impairs talin-induced αIIbβ3 activation in transfected CHO cells and blunts αvβ3-mediated adhesion and migration of endothelial cells. Our results thus identify kindlin-2 as a novel regulator of integrin activation; it functions as a coactivator.

/pdf/kindlin-2-mig-2-a-co-activator-of-b3-integrins-2bdjow3c14.pdf

Chuanyue Wu

Papers

Breaking the Integrin Hinge A DEFINED STRUCTURAL CONSTRAINT REGULATES INTEGRIN SIGNALING

Integrin-linked kinase (ILK) and its interactors: a new paradigm for the coupling of extracellular matrix to actin cytoskeleton and signaling complexes

Migfilin and Mig-2 link focal adhesions to filamin and the actin cytoskeleton and function in cell shape modulation.

Kindlin-2 (Mig-2): a co-activator of β3 integrins

Integrin activation and cytoskeletal interaction are essential for the assembly of a fibronectin matrix.