Cell Adhesion & Migration
ISSN: 1933-6918 (Print) 1933-6926 (Online) Journal homepage: http://www.tandfonline.com/loi/kcam20
Foreword Ira Daar To cite this article: Ira Daar (2014) Foreword, Cell Adhesion & Migration, 8:4, 293-293, DOI: 10.4161/19336918.2014.987059 To link to this article: http://dx.doi.org/10.4161/19336918.2014.987059
Accepted author version posted online: 17 Nov 2014.
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Date: 05 November 2015, At: 17:12
FOREWORD Cell Adhesion & Migration 8:4, 293; July/August 2014; © 2014 Taylor & Francis Group, LLC
Foreword Ira Daar*
Downloaded by [117.244.25.8] at 17:12 05 November 2015
Developmental Signal Transduction Section; Laboratory of Cell and Developmental Signaling; National Cancer Institute-Frederick; Frederick, MD USA
Eph/ephrin signaling has a well recognized role in the control of cell adhesion and repulsion, cell migration, and morphogenesis during development. Eph family members have been implicated in regulating numerous processes, including axon outgrowth, neural crest and retinal progenitor cell migration, hindbrain segmentation, skeletal patterning, mesoderm/ectoderm boundary formation, angiogenesis, and tumor progression. Eph receptors and ephrin ligands signal in a bi-directional manner, where both molecules transmit intracellular signals upon cell-cell contact. These interactions induce cell repulsive or attractive responses in several cell types, and may have different effects within a sub-population of cells. Unlike the Eph receptors that possess tyrosine kinase activity, the ephrin ligands do not possess intrinsic catalytic activity for signaling. The transmembrane B-type ligands rely upon a scaffolding activity that recruits signaling molecules to transmit an effect on cell function, and it is also clear that the Eph receptors have kinase-independent signaling activities as well.
Many reviews over the past several years have focused on the intricate mechanisms of both “forward” signaling through the Eph receptors and “reverse” signaling through the intracellular domain of ephrin ligands. In this special focus issue, we have a series of reviews examining important but less highlighted aspects of Eph/ephrin signaling. In the following reviews, the reader will be introduced to: (1) the conflicting evidence for the roles for Eph/ephrin signaling in neurogenesis, and use of mathematical modeling to conceivably reconcile such results; (2) an examination of the key code of Eph/ephrin interactions critical for tissue separation during development, and exploring the evidence that these molecules are systematically used to induce local repulsion at contacts between different cell types to prevent mixing of adjacent cell populations; (3) the evidence for Eph receptor and ephrin signaling in regulating proliferation and differentiation, which is one of the under appreciated aspects of Eph/ephrin signaling; (4) how Eph receptors and ephrins modulate diverse epithelial cell responses in a
context-dependent manner, and a possible role for aberrant Eph/ephrin signaling affecting cell-cell communication in the disease state; (5) a review emphasizing the role of Eph/ephrin molecules in angiogenesis, and the emerging evidence that links these molecules to the function of other receptor tyrosine kinases and cell surface receptors to act as a hub for receptor endocytosis in the vasculature; (6) specific proteases that cleave the receptors or ligands, and the role of these proteases in promoting shedding, as well as the regulation of receptor/ligand internalization and signaling; (7) another mode of the regulation of Eph/ephrin signaling (besides the commonly examined Eph-ephrin interactions) through homotypic Eph-Eph interactions that modulate the initiation of Eph/ephrin signaling. These reviews emphasize less well known aspects of Eph/ephrin signaling, will hopefully provide the reader with interesting new insights into these important multi-functional molecules.
*Correspondence to: Ira Daar; Email: [email protected] http://dx.doi.org/10.4161/19336918.2014.987059
www.landesbioscience.com
Cell Adhesion & Migration
293
ISSN: 1933-6918 (Print) 1933-6926 (Online) Journal homepage: http://www.tandfonline.com/loi/kcam20
Foreword Ira Daar To cite this article: Ira Daar (2014) Foreword, Cell Adhesion & Migration, 8:4, 293-293, DOI: 10.4161/19336918.2014.987059 To link to this article: http://dx.doi.org/10.4161/19336918.2014.987059
Accepted author version posted online: 17 Nov 2014.
Submit your article to this journal
Article views: 38
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=kcam20 Download by: [117.244.25.8]
Date: 05 November 2015, At: 17:12
FOREWORD Cell Adhesion & Migration 8:4, 293; July/August 2014; © 2014 Taylor & Francis Group, LLC
Foreword Ira Daar*
Downloaded by [117.244.25.8] at 17:12 05 November 2015
Developmental Signal Transduction Section; Laboratory of Cell and Developmental Signaling; National Cancer Institute-Frederick; Frederick, MD USA
Eph/ephrin signaling has a well recognized role in the control of cell adhesion and repulsion, cell migration, and morphogenesis during development. Eph family members have been implicated in regulating numerous processes, including axon outgrowth, neural crest and retinal progenitor cell migration, hindbrain segmentation, skeletal patterning, mesoderm/ectoderm boundary formation, angiogenesis, and tumor progression. Eph receptors and ephrin ligands signal in a bi-directional manner, where both molecules transmit intracellular signals upon cell-cell contact. These interactions induce cell repulsive or attractive responses in several cell types, and may have different effects within a sub-population of cells. Unlike the Eph receptors that possess tyrosine kinase activity, the ephrin ligands do not possess intrinsic catalytic activity for signaling. The transmembrane B-type ligands rely upon a scaffolding activity that recruits signaling molecules to transmit an effect on cell function, and it is also clear that the Eph receptors have kinase-independent signaling activities as well.
Many reviews over the past several years have focused on the intricate mechanisms of both “forward” signaling through the Eph receptors and “reverse” signaling through the intracellular domain of ephrin ligands. In this special focus issue, we have a series of reviews examining important but less highlighted aspects of Eph/ephrin signaling. In the following reviews, the reader will be introduced to: (1) the conflicting evidence for the roles for Eph/ephrin signaling in neurogenesis, and use of mathematical modeling to conceivably reconcile such results; (2) an examination of the key code of Eph/ephrin interactions critical for tissue separation during development, and exploring the evidence that these molecules are systematically used to induce local repulsion at contacts between different cell types to prevent mixing of adjacent cell populations; (3) the evidence for Eph receptor and ephrin signaling in regulating proliferation and differentiation, which is one of the under appreciated aspects of Eph/ephrin signaling; (4) how Eph receptors and ephrins modulate diverse epithelial cell responses in a
context-dependent manner, and a possible role for aberrant Eph/ephrin signaling affecting cell-cell communication in the disease state; (5) a review emphasizing the role of Eph/ephrin molecules in angiogenesis, and the emerging evidence that links these molecules to the function of other receptor tyrosine kinases and cell surface receptors to act as a hub for receptor endocytosis in the vasculature; (6) specific proteases that cleave the receptors or ligands, and the role of these proteases in promoting shedding, as well as the regulation of receptor/ligand internalization and signaling; (7) another mode of the regulation of Eph/ephrin signaling (besides the commonly examined Eph-ephrin interactions) through homotypic Eph-Eph interactions that modulate the initiation of Eph/ephrin signaling. These reviews emphasize less well known aspects of Eph/ephrin signaling, will hopefully provide the reader with interesting new insights into these important multi-functional molecules.
*Correspondence to: Ira Daar; Email: [email protected] http://dx.doi.org/10.4161/19336918.2014.987059
www.landesbioscience.com
Cell Adhesion & Migration
293
