Expression and developmental regulation of Ehk-1, a neuronal Elk-like receptor tyrosine kinase in brain

doi:10.1016/0306-4522(94)90014-0

Neuroscience

Volume 63, Issue 1, November 1994, Pages 163-178

https://doi.org/10.1016/0306-4522(94)90014-0 Get rights and content

Abstract

Protein tyrosine kinases are pivotal in central nervous tissue development and maintenance. Here we focus on the expression of Ehk-1, a novel Elk-related receptor tyrosine kinase.Ehk-1 gene expression is observed in the developing and adult central nervous system and is highly regulated throughout development at both the messenger RNA and protein levels. Three messenger RNA transcripts of 8.5, 5.9 and 5.1 kb are detectable in the rat brain and a variety of splice possibilities have been identified. However, a major protein species of aroundM, 120,000 predominates throughout development. Ehk-1 messenger RNA and protein levels are highest in the first postnatal week. Byin situ messenger RNA hybridization the gene is expressed by all neurons of the adult brain, but mostly in the hippocampus, cerebral cortex and large neurons of the deep cerebellar nuclei, as well as the Purkinje and granular cells of the cerebellum. At earlier stages of development, transcripts are most prominent in the periventricular germinal layers of the brain. Immunohistochemistry reveals a pronounced membrane associated protein expression in immature neurons. In the adult animal, peak reactivity was found in the neuropil with sparing of most perikarya. The spatial and temporal pattern ofehk-1 gene expression suggests a role in both the development and maintenance of differentiated neurons of the central nervous system.

References (41)

BarresB.A. et al.
Cell death and control of cell survival in the oligodendrocyte lineage
Cell
(1992)
BoydA.W. et al.
Isolation and characterization of a novel receptor-type protein tyrosine kinase (hek) from a human pre-B cell line
J. biol. Chem.
(1992)
BradfordM.M.
A rapid and sensitive method for the quantitation of microgram quantities of protein utilising the principle of protein dye binding
Analyt. Biochem.
(1976)
ChomczynskiP. et al.
Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction
Analyt. Biochem.
(1987)
FeinbergA.P. et al.
A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity
Analyt. Biochem.
(1983)
HoneggerP. et al.
Developmental effects of basic fibroblast growth factor and platelet-derived growth factor on glial cells in a three-dimensional cell culture system
J. Neuroimmun.
(1992)
HunterT.
A thousand and one protein kinases
Cell
(1987)
KilpatrickT.J. et al.
Cloning and growth of multipotential neural precursors: requirements for proliferation and differentiation
Neuron
(1993)
LaiC. et al.
An extended family of protein-tyrosine kinase genes differentially expressed in the vertebrate nervous system
Neuron
(1991)
LenoirD. et al.
Insulin-like growth factor I (IGF-I) stimulates DNA synthesis in fetal rat brain cell cultures
Devl Brain Res.
(1983)

RaffM.C. et al.

Reconstitution of a developmental clockin vitro: a critical role for strocytes in the timing of oligodendrocyte differentiation

Cell

(1985)

SchlessingerJ. et al.

Growth factor signaling by receptor tyrosine kinases

Neuron

(1992)

UllrichA. et al.

Signal transduction by receptors with tyrosine kinase activity

Cell

(1990)

VassK. et al.

Induction of stress protein HSP70 in nerve cells after status epilepticus in the rat

Neurosci. Lett.

(1989)

WiglerM. et al.

Biochemical transfer of single-copy eucaryotic genes using total cellular DNA as donor

Cell

(1978)

BreitschopfH. et al.

In situ hybridization with digoxigenin-labeled probes: sensitive and reliable detection method applied to myelinating rat brain

Acta neuropath. Berlin

(1992)

ChanJ. et al.

eek and erk, new members of the eph subclass of receptor protein-tyrosine kinases

Oncogene

(1991)

CohenB. et al.

Tyrosine phosphorylation is a signal for the trafficking of pp85, an 85-kDa phosphorylated polypeptide associated with phosphatidylinositol kinase activity

GilardiH.P. et al.

An Eph-related receptor protein tyrosine kinase gene segmentally expressed in the developing mouse hindbrain

Oncogene

(1992)

HanksS.K. et al.

The protein kinase family: conserved features and deduced phylogeny of the catalytic domains

Science

(1988)

Cited by (31)

Receptor tyrosine kinase EphA5 is a functional molecular target in human lung cancer
2015, Journal of Biological Chemistry
Citation Excerpt :
Ephrin receptors belong to a family of closely related proteins with diverse functions in both normal physiology and disease pathogenesis (15, 16). EphA5 is mostly recognized for its critical role in axonal guidance during embryonic development (17–19); its involvement in cancer is only now becoming evident (20–22). Here, we identify EphA5 as a molecular target of lung cancer and as a novel regulator of IR-induced cell cycle checkpoint and DNA damage repair, with unexpected roles in the resistance of lung cancer to radiotherapy.
Lung cancer is often refractory to radiotherapy, but molecular mechanisms of tumor resistance remain poorly defined. Here we show that the receptor tyrosine kinase EphA5 is specifically overexpressed in lung cancer and is involved in regulating cellular responses to genotoxic insult. In the absence of EphA5, lung cancer cells displayed a defective G₁/S cell cycle checkpoint, were unable to resolve DNA damage, and became radiosensitive. Upon irradiation, EphA5 was transported into the nucleus where it interacted with activated ATM (ataxia-telangiectasia mutated) at sites of DNA repair. Finally, we demonstrate that a new monoclonal antibody against human EphA5 sensitized lung cancer cells and human lung cancer xenografts to radiotherapy and significantly prolonged survival, thus suggesting the likelihood of translational applications.
Altered EphA5 mRNA expression in rat brain with a single methamphetamine treatment
2007, Neuroscience Letters
Methamphetamine is a potent and indirect dopaminergic agonist which can cause chronic brain dysfunctions including drug abuse, drug dependence and drug-induced psychosis. Methamphetamine is known to trigger molecular mechanisms involved in associative learning and memory, and thereby alter patterns of synaptic connectivity. The persistent risk of relapse in methamphetamine abuse, dependence and psychosis may be caused by such alterations in synaptic connectivity. EphA5 receptors constitute large families of tyrosine kinase receptor and are expressed almost exclusively in the nervous system, especially in the limbic structures. Recent studies suggest EphA5 to be important in the topographic projection, development, and plasticity of limbic structures, and to be involved in dopaminergic neurotransmission. We used in situ hybridization to examine whether methamphetamine alters EphA5 mRNA expression in the brains of adult male Wister rats. EphA5 mRNA was widely distributed in the medial frontal cortex, cingulate cortex, piriform cortex, hippocampus, habenular nucleus and amygdala. Compared to baseline expression at 0 h, EphA5 mRNA was significantly decreased (by 20%) in the medial frontal cortex at 24 h, significantly increased (by 30%) in the amygdala at 9 and 24 h, significantly but transiently decreased (by 30%) in the habenular nucleus at 1 h after a single injection of methamphetamine. Methamphetamine did not change EphA5 mRNA expression in the cingulate cortex, piriform cortex or hippocampus. Our results that methamphetamine altered EphA5 mRNA expression in rat brain suggest methamphetamine could affect patterns of synaptic connectivity, which might be responsible for methamphetamine-induced chronic brain dysfunctions.
Functions of ephrin/Eph interactions in the development of the nervous system: Emphasis on the hippocampal system
2005, Brain Research Reviews
Ephrins and their Eph receptors are membrane-anchored proteins that have key roles in the development of the Central Nervous System. The main characteristics of ephrin/Eph interactions are that their effect is mediated by cell-to-cell contacts and that they can propagate bidirectional signals downstream of the ligand–receptor complex. These characteristics make ephrins and Eph receptors critical cues in the regulation of migrating cells or axons, and in the establishment of tissue patterns and topographic maps in distinct regions of the developing brain. In addition, ephrins and Eph receptors regulate synapse formation and plasticity. These roles would be promoted by complementary gradual expression of receptors and ligands in the neurons involved. Although, historically, ephrins and Eph receptors have been considered as repulsion signals through barriers or gradients, new evidence indicates that they may be both inhibitory and permissive/active cues depending on expression levels. The expression of distinct ligands and receptors in the developing and mature hippocampus suggests that these proteins are involved in distinct processes during the development and maturation of the hippocampal region. In fact, recent studies have shown that ephrin/Eph signaling participates in the formation of the layer-specific patterns of hippocampal afferents, in synaptogenesis and in plasticity. Therefore, ephrin/Eph interactions should be considered a crucial system in the development and maturation of the brain regions, including the hippocampus.
Disruption of ephrin-A/EphA binding alters synaptogenesis and neural connectivity in the hippocampus
2005, Neuroscience
Ephrins are guidance cues that modulate axonal growth and the subsequent axonal topographic maps in many regions of the CNS. Here we studied the functional roles of ephrin-A/EphA interactions in the layer-specific pattern of axonal projections in the hippocampus by disrupting the ephrin-A signaling by over-expression of a soluble EphA receptor. Tracing experiments in EphA5-Fc over-expressing mice revealed that reduction of ephrin-A/EphA interactions did not affect the proper distribution of the main hippocampal afferents, i.e. entorhinal and commissural projections. However, further ultrastructural analyses showed a reduction in the density of synaptic terminals in the entorhinal and commissural termination layers in these mice. In addition, using anti-calbindin antibodies, we analyzed the dentate mossy fiber projections following disruption of ephrin-A/EphA interactions throughout developing hippocampus. While the main mossy fiber bundle appeared normal, the infrapyramidal bundle formed longer projections that established ectopic contacts in these transgenic mice. Later, the expected specific pruning of the infrapyramidal bundle was not observed at adult stages. Ultrastructural analyses confirmed a higher number of mossy fiber terminals in the infrapyramidal bundle in adult EphA5-Fc transgenic mice and showed that these terminals were larger and established a greater number of contacts than in controls. Our results demonstrate that ephrin-A/EphA interactions regulate the synaptogenesis of hippocampal afferents and the proper development and refinement of granule cell projections.
New molecules for hippocampal development
2001, Trends in Neurosciences
Pathfinding by developing axons towards their proper targets is an essential step in establishing appropriate neuronal connections. Recent work involving cell culture assays and molecular biology strategies, including knockout animals, strongly indicates that a complex network of guidance signals regulates the formation of hippocampal connections during development. Outgrowing axons are routed towards the hippocampal formation by specific expression of long-range cues, which include secreted class 3 semaphorins, netrin 1 and Slit proteins. Local membrane- or substrate-anchored molecules, such as ligands of the ephrin A subclass, provide layer-specific positional information. Understanding the molecular mechanisms that underlie axonal guidance during hippocampal development might be of importance in making therapeutic use of sprouting fibers, which are produced following the loss of afferents in CNS lesion.
Eph receptors and ephrins: Regulators of guidance and assembly
2000, International Review of Cytology
Recent advances have started to elucidate the developmental functions and biochemistry of Eph receptor tyrosine kinases and their membrane-bound ligands, ephrins. Interactions between these molecules are promiscuous, but they largely fall into two groups: EphA receptors bind to GPI-anchored ephrin-A ligands, while EphB receptors bind to ephrin-B proteins that have a transmembrane and cytoplasmic domain. Remarkably, ephrin-B proteins transduce signals, such that bidirectional signaling can occur upon interaction with Eph receptor. In many tissues, specific Eph receptors and ephrins have complementary domains, whereas other family members may overlap in their expression. An important role of Eph receptors and ephrins is to mediate cell-contact-dependent repulsion. Complementary and overlapping gradients of expression underlie establishment of a topographic map of neuronal projections in the retinotectal system. Eph receptors and ephrins also act at boundaries to channel neuronal growth cones along specific pathways, restrict the migration of neural crest cells, and via bidirectional signaling prevent intermingling between hindbrain segments. Intriguingly, Eph receptors and ephrins can also trigger an adhesive response of endothelial cells and are required for the remodeling of blood vessels. Biochemical studies suggest that the extent of multimerization of Eph receptors modulates the cellular response and that the actin cytoskeleton is one major target of the intracellular pathways activated by Eph receptors. Eph receptors and ephrins have thus emerged as key regulators of the repulsion and adhesion of cells that underlie the establishment, maintainence, and remodeling of patterns of cellular organization.

View all citing articles on Scopus

View full text

Expression and developmental regulation of Ehk-1, a neuronal Elk-like receptor tyrosine kinase in brain

Abstract

Cell

J. biol. Chem.

Analyt. Biochem.

Analyt. Biochem.

Analyt. Biochem.

J. Neuroimmun.

Cell

Neuron

Neuron

Devl Brain Res.

Cell

Neuron

Cell

Neurosci. Lett.

Cell

In situ hybridization with digoxigenin-labeled probes: sensitive and reliable detection method applied to myelinating rat brain

Acta neuropath. Berlin

eek and erk, new members of the eph subclass of receptor protein-tyrosine kinases

Oncogene

Tyrosine phosphorylation is a signal for the trafficking of pp85, an 85-kDa phosphorylated polypeptide associated with phosphatidylinositol kinase activity

An Eph-related receptor protein tyrosine kinase gene segmentally expressed in the developing mouse hindbrain

Oncogene

The protein kinase family: conserved features and deduced phylogeny of the catalytic domains

Science