EphB1, an erythropoietin-producing hepatoma (Eph) receptor tyrosine kinase, is crucial in multiple biological processes. EphB1-mediated forward and ephrin ligand-mediated reverse signalings, known as bidirectional signaling, regulate cell migration, adhesion, morphological changes, differentiation, proliferation, and survival via cell-cell communication. This signaling is involved in pathways related to the development of the central nervous system, immune organs, and also in angiogenesis [1].

In brain development, EphB1 is required for proper guidance of cortical axon projections. Conditional knockout (cKO) of EphB1 in GABAergic cells (Vgat-Cre), but not in cortical excitatory neurons (Emx1-Cre), reproduced the cortical axon guidance defects seen in global EphB1 knockout (KO) mice. This suggests a cell non-autonomous role of EphB1 in GABAergic cells to influence proper cortical glutamatergic axon guidance [3]. In endothelial cells, EphB1 interacts with caveolin-1 (Cav-1), a key structural protein of caveolae. Deletion of the Cav-1 scaffold domain binding (CSD) motif in EphB1 in EphB1-deficient (EphB1-/-) mice reduced Cav-1 protein expression and caveolae numbers, indicating its role in caveolae biogenesis [2]. In acute myelogenous leukemia (AML), EphB1 restoration led to activation of the DNA damage response (DDR) cascade, promoting programmed cell death. EphB1 repression was associated with poor overall survival in pediatric AML, revealing its tumor-suppressor function [4].

In conclusion, EphB1 is essential for normal development and function in the nervous and endothelial systems, as well as in regulating cell survival in leukemia. Studies using EphB1 KO and CKO mouse models have provided significant insights into its role in these biological processes and disease conditions, highlighting its potential as a therapeutic target.

References:

1. Wei, Wenqiang, Wang, Hongju, Ji, Shaoping. 2017. Paradoxes of the EphB1 receptor in malignant brain tumors. In Cancer cell international, 17, 21. doi:10.1186/s12935-017-0384-z. https://pubmed.ncbi.nlm.nih.gov/28194092/

2. Tiruppathi, Chinnaswamy, Regmi, Sushil C, Wang, Dong-Mei, Rehman, Jalees, Malik, Asrar B. 2020. EphB1 interaction with caveolin-1 in endothelial cells modulates caveolae biogenesis. In Molecular biology of the cell, 31, 1167-1182. doi:10.1091/mbc.E19-12-0713. https://pubmed.ncbi.nlm.nih.gov/32238105/

3. Assali, Ahlem, Chenaux, George, Cho, Jennifer Y, Ehrlich, Nathan A, Cowan, Christopher W. 2024. EphB1 controls long-range cortical axon guidance through a cell non-autonomous role in GABAergic cells. In Development (Cambridge, England), 151, . doi:10.1242/dev.201439. https://pubmed.ncbi.nlm.nih.gov/38345254/

4. Kampen, K R, Scherpen, F J G, Garcia-Manero, G, Kornblau, S M, De Bont, E S J M. 2015. EphB1 Suppression in Acute Myelogenous Leukemia: Regulating the DNA Damage Control System. In Molecular cancer research : MCR, 13, 982-92. doi:10.1158/1541-7786.MCR-14-0660-T. https://pubmed.ncbi.nlm.nih.gov/25944917/