EPHB3

Ephrin Type-A Receptor 8 (EPHA8)

Ephrin type-A receptor 8, commonly referred to as EPHA8, is a member of the ephrin receptor subfamily of the protein-tyrosine kinase family. Ephrin receptors are involved in mediating developmental processes, particularly in the nervous system. EPHA8 is encoded by the EPHA8 gene in humans.

Structure

EPHA8 is a transmembrane protein that consists of several distinct domains:

• Extracellular domain: This domain is responsible for binding to ephrin ligands. It contains a ligand-binding domain, a cysteine-rich region, and two fibronectin type III repeats.
• Transmembrane domain: This hydrophobic region anchors the receptor in the cell membrane.
• Intracellular domain: This domain includes a juxtamembrane region, a tyrosine kinase domain, and a sterile alpha motif (SAM) domain. The kinase domain is crucial for the receptor's signaling capabilities.

Function

EPHA8 plays a significant role in the development of the nervous system. It is involved in axon guidance, which is the process by which neurons send out axons to reach the correct targets. EPHA8 interacts with ephrin-A ligands, leading to bidirectional signaling that affects both the receptor-expressing and ligand-expressing cells.

Axon Guidance

EPHA8 is particularly important in the formation of the topographic maps in the visual system. It helps guide retinal ganglion cell axons to their appropriate targets in the brain, ensuring proper visual processing.

Cell Adhesion and Migration

EPHA8 also influences cell adhesion and migration, processes that are critical during embryonic development and in the adult brain for synaptic plasticity.

Expression

EPHA8 is predominantly expressed in the developing nervous system, including the brain and spinal cord. Its expression is tightly regulated during development, and it is also found in certain regions of the adult brain.

Clinical Significance

Alterations in EPHA8 expression or function have been implicated in various neurological disorders. Research is ongoing to determine the exact role of EPHA8 in these conditions and its potential as a therapeutic target.

Research

Studies on EPHA8 involve understanding its role in neural development and its potential involvement in neurodegenerative diseases. Animal models, such as mice with targeted deletions of the EPHA8 gene, are used to study its function in vivo.

Also see

• Ephrin receptor
• Axon guidance
• Neurodevelopment
• Protein-tyrosine kinase

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