scholarly journals Regulation of the EphA2 receptor intracellular region by phosphomimetic negative charges in the kinase-SAM linker

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bernhard C. Lechtenberg ◽  
Marina P. Gehring ◽  
Taylor P. Light ◽  
Christopher R. Horne ◽  
Mike W. Matsumoto ◽  
...  
Keyword(s):  
Structural Biology ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Structural Information ◽  
Cell Communication ◽  
Kinase Domain ◽  
Eph Receptor ◽  
Structure And Dynamics ◽  
Signaling Mechanisms ◽  
Intracellular Region

AbstractEph receptor tyrosine kinases play a key role in cell-cell communication. Lack of structural information on the entire multi-domain intracellular region of any Eph receptor has hindered understanding of their signaling mechanisms. Here, we use integrative structural biology to investigate the structure and dynamics of the EphA2 intracellular region. EphA2 promotes cancer malignancy through a poorly understood non-canonical form of signaling involving serine/threonine phosphorylation of the linker connecting its kinase and SAM domains. We show that accumulation of multiple linker negative charges, mimicking phosphorylation, induces cooperative changes in the EphA2 intracellular region from more closed to more extended conformations and perturbs the EphA2 juxtamembrane segment and kinase domain. In cells, linker negative charges promote EphA2 oligomerization. We also identify multiple kinases catalyzing linker phosphorylation. Our findings suggest multiple effects of linker phosphorylation on EphA2 signaling and imply that coordination of different kinases is necessary to promote EphA2 non-canonical signaling.

scholarly journals Allosteric Regulation of the EphA2 Receptor Intracellular Region by Serine/Threonine Kinases

2021 ◽  
Author(s):  
Bernhard C. Lechtenberg ◽  
Marina P. Gehring ◽  
Taylor P. Light ◽  
Mike W. Matsumoto ◽  
Kalina Hristova ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Molecular Mechanisms ◽  
Structural Information ◽  
Cell Communication ◽  
Kinase Domain ◽  
Eph Receptor ◽  
X Ray ◽  
X Ray Crystallography ◽  
Exchange Mass Spectrometry ◽  
Intracellular Region

ABSTRACTEph receptor tyrosine kinases play a key role in cell-cell communication. However, lack of structural information on the entire multi-domain intracellular region of any Eph receptor has hindered detailed understanding of their signaling mechanisms. Here, we use an integrative structural biology approach combining X-ray crystallography, small-angle X-ray scattering and hydrogen-deuterium exchange mass spectrometry, to gain the first insights into the structure and dynamics of the entire EphA2 intracellular region. EphA2 promotes cancer malignancy through a poorly understood non-canonical form of signaling that depends on serine/threonine phosphorylation of the linker connecting the EphA2 kinase and SAM domains. We uncovered two distinct molecular mechanisms that may function in concert to mediate the effects of linker phosphorylation through an orchestrated allosteric regulatory network. The first involves a shift in the equilibrium between a “closed” configuration of the EphA2 intracellular region and an “open” more extended configuration induced by the accumulation of phosphorylation sites in the linker. This implies that cooperation of multiple serine/threonine kinase signaling networks is necessary to promote robust EphA2 non-canonical signaling. The second involves allosteric rearrangements in the kinase domain and juxtamembrane segment induced by phosphorylation of some linker residues, suggesting a link between EphA2 non-canonical signaling and canonical signaling through tyrosine phosphorylation. Given the key role of EphA2 in cancer malignancy, this new knowledge can inform therapeutic strategies.

scholarly journals Evolution of functional diversity in the holozoan tyrosine kinome

2021 ◽  
Author(s):  
Wayland Yeung ◽  
Annie Kwon ◽  
Rahil Taujale ◽  
Claire Bunn ◽  
Aarya Venkat ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Cell Communication ◽  
Kinase Domain ◽  
Model Organisms ◽  
Post Translational Modification ◽  
Functional Features ◽  
Conformational Regulation ◽  
Insulin Receptor Kinase

The emergence of multicellularity is strongly correlated with the expansion of tyrosine kinases, a conserved family of signaling enzymes that regulates pathways essential for cell-to-cell communication. Although tyrosine kinases have been classified from several model organisms, a molecular-level understanding of tyrosine kinase evolution across all holozoans is currently lacking. Using a hierarchical sequence constraint-based classification of diverse holozoan tyrosine kinases, we construct a new phylogenetic tree that identifies two ancient clades of cytoplasmic and receptor tyrosine kinases separated by the presence of an extended insert segment in the kinase domain connecting the D and E-helices. Present in nearly all receptor tyrosine kinases, this fast-evolving insertion imparts diverse functionalities such as post-translational modification sites and regulatory interactions. The two exceptions which lack this insert, Eph and EGFR receptor tyrosine kinases, each form an independent lineage characterized by unique functional features. We also identify common constraints shared across multiple tyrosine kinase families which warrant the designation of three new subgroups: Src module (SrcM), insulin receptor kinase-like (IRKL), and Fibroblast, Vascular, and Platelet-derived growth factor Receptors (FPVR). Subgroup-specific constraints reflect shared autoinhibitory interactions involved in kinase conformational regulation. Conservation analyses describe how diverse tyrosine kinase signaling functions arose through the addition of family-specific motifs upon subgroup-specific features and co-conserved protein domains. We propose the oldest tyrosine kinases, IRKL, SrcM and Csk, originated from unicellular pre-metazoans and were co-opted for complex multicellular functions. The increased frequency of oncogenic variants in more recent tyrosine kinases suggests that lineage-specific functionalities are selectively altered in human cancers.

scholarly journals Evolution of functional diversity in the holozoan tyrosine kinome

2021 ◽  
Author(s):  
Wayland Yeung ◽  
Annie Kwon ◽  
Rahil Taujale ◽  
Claire Bunn ◽  
Aarya Venkat ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Cell Communication ◽  
Kinase Domain ◽  
Model Organisms ◽  
Post Translational Modification ◽  
Functional Features ◽  
Conformational Regulation ◽  
Insulin Receptor Kinase

Abstract The emergence of multicellularity is strongly correlated with the expansion of tyrosine kinases, a conserved family of signaling enzymes that regulates pathways essential for cell-to-cell communication. Although tyrosine kinases have been classified from several model organisms, a molecular-level understanding of tyrosine kinase evolution across all holozoans is currently lacking. Using a hierarchical sequence constraint-based classification of diverse holozoan tyrosine kinases, we construct a new phylogenetic tree that identifies two ancient clades of cytoplasmic and receptor tyrosine kinases separated by the presence of an extended insert segment in the kinase domain connecting the D and E-helices. Present in nearly all receptor tyrosine kinases, this fast-evolving insertion imparts diverse functionalities such as post-translational modification sites and regulatory interactions. Eph and EGFR receptor tyrosine kinases are two exceptions which lack this insert, each forming an independent lineage characterized by unique functional features. We also identify common constraints shared across multiple tyrosine kinase families which warrant the designation of three new subgroups: Src Module (SrcM), Insulin Receptor Kinase-Like (IRKL), and Fibroblast, Platelet-derived, Vascular, and growth factor Receptors (FPVR). Subgroup-specific constraints reflect shared autoinhibitory interactions involved in kinase conformational regulation. Conservation analyses describe how diverse tyrosine kinase signaling functions arose through the addition of family-specific motifs upon subgroup-specific features and co-evolving protein domains. We propose the oldest tyrosine kinases, IRKL, SrcM, and Csk, originated from unicellular pre-metazoans and were co-opted for complex multicellular functions. The increased frequency of oncogenic variants in more recent tyrosine kinases suggests that lineage-specific functionalities are selectively altered in human cancers.

scholarly journals In vitro guidance of retinal ganglion cell axons by RAGS, a 25 kDa tectal protein related to ligands for Eph receptor tyrosine kinases

Cell ◽  
1995 ◽  
Vol 82 (3) ◽  
pp. 359-370 ◽  
Author(s):  
Uwe Drescher ◽  
Claus Kremoser ◽  
Claudia Handwerker ◽  
Jürgen Löschinger ◽  
Masaharu Noda ◽  
...  
Keyword(s):  
Ganglion Cell ◽  
Retinal Ganglion Cell ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Retinal Ganglion ◽  
Eph Receptor

scholarly journals A new ephrin-A1 isoform (ephrin-A1b) with altered receptor binding properties abrogates the cleavage of ephrin-A1a

2004 ◽  
Vol 379 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Eivind F. FINNE ◽  
Else MUNTHE ◽  
Hans-Christian AASHEIM
Keyword(s):  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Transcript Level ◽  
Binding Properties ◽  
Eph Receptor ◽  
Cleavage Process ◽  
293 Cells ◽  
Significant Expression ◽  
Isoform B ◽  
Epha Receptor

Ephrins are ligands for the Eph receptor tyrosine kinases, which play important roles in patterning nervous and vascular systems. Ephrin-A1 is a glycosylphosphatidylinositol-anchored ligand that binds to the EphA receptor tyrosine kinases. In the present study, we have identified a new ephrin-A1 isoform, denoted ephrin-A1b (ephrin-A1 isoform b). Compared with the originally described ephrin-A1 sequence, ephrin-A1a [Holzman, Marks and Dixit (1990) Mol. Cell. Biol. 10, 5830–5838], ephrin-A1b lacks a segment of 22 amino acids (residues 131–152). At the transcript level, exon 3 is spliced out in the transcript encoding ephrin-A1b. Transfection of HEK-293T cells (human embryonic kidney 293 cells) with an ephrin-A1b-expressing plasmid resulted in a significant expression of the protein on the cell surface. However, soluble EphA2 receptor (EphA2-Fc) bound weakly to ephrin-A1b-expressing transfectants, but bound strongly to ephrin-A1a-expressing transfectants. Ephrins have been shown to undergo regulated cleavage after interaction with their receptors. This process is inhibited by co-expression of ephrin-A1a and ephrin-A1b, indicating that ephrin-A1b influences the cleavage process. Taken together, these findings indicate that this newly described isoform may regulate the function of its ephrin-A1a counterpart.

scholarly journals Quantifying the strength of heterointeractions among receptor tyrosine kinases from different subfamilies: Implications for cell signaling

2020 ◽  
Vol 295 (29) ◽  
pp. 9917-9933 ◽  
Author(s):  
Michael D. Paul ◽  
Hana N. Grubb ◽  
Kalina Hristova
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Growth Factor Receptor ◽  
Vascular Endothelial ◽  
Eph Receptor ◽  
Vital Cell ◽  
Cell Processes ◽  
Epidermal Growth ◽  
Endothelial Growth Factor

Receptor tyrosine kinases (RTKs) are single-pass membrane proteins that control vital cell processes such as cell growth, survival, and differentiation. There is a growing body of evidence that RTKs from different subfamilies can interact and that these diverse interactions can have important biological consequences. However, these heterointeractions are often ignored, and their strengths are unknown. In this work, we studied the heterointeractions of nine RTK pairs, epidermal growth factor receptor (EGFR)–EPH receptor A2 (EPHA2), EGFR–vascular endothelial growth factor receptor 2 (VEGFR2), EPHA2–VEGFR2, EPHA2–fibroblast growth factor receptor 1 (FGFR1), EPHA2–FGFR2, EPHA2–FGFR3, VEGFR2–FGFR1, VEGFR2–FGFR2, and VEGFR2–FGFR3, using a FRET-based method. Surprisingly, we found that RTK heterodimerization and homodimerization strengths can be similar, underscoring the significance of RTK heterointeractions in signaling. We discuss how these heterointeractions can contribute to the complexity of RTK signal transduction, and we highlight the utility of quantitative FRET for probing multiple interactions in the plasma membrane.

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