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Gene Review

PLXNB1  -  plexin B1

Homo sapiens

Synonyms: KIAA0407, PLEXIN-B1, PLXN5, Plexin-B1, SEP, ...
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Disease relevance of PLXNB1


Psychiatry related information on PLXNB1

  • One of the CJD patients had a normal size SEP, and neither patient showed hyperexcitability in SEP-recovery at C-T intervals of 20-60 msec at which there was marked MEP potentiation [6].

High impact information on PLXNB1

  • Recent findings shed new light on the signalling network downstream of semaphorins and plexins by demonstrating that one of the plexins, plexin-B1, possesses an intrinsic GTPase-activating protein (GAP) activity towards R-Ras [7].
  • Inactivation of R-Ras by the plexin-B1 GAP domains is required for plexin-B1-mediated effects on the cytoskeleton [7].
  • Oral penicillamine therapy led to a decrease in auditory brainstem (ABP) and somatosensory (SEP) conduction times in 6 and 4 neurologically symptomatic patients, respectively [8].
  • Plexin-B1/RhoGEF-mediated RhoA activation involves the receptor tyrosine kinase ErbB-2 [9].
  • Binding of Sema4D to plexin-B1 stimulates the intrinsic tyrosine kinase activity of ErbB-2, resulting in the phosphorylation of both plexin-B1 and ErbB-2 [9].

Biological context of PLXNB1


Anatomical context of PLXNB1


Associations of PLXNB1 with chemical compounds

  • Here, we show that plexin-B family members stably associate with the receptor tyrosine kinase ErbB-2 [9].
  • Interaction of plexin-B1 with PDZ domain-containing Rho guanine nucleotide exchange factors [13].
  • We report that the Semaphorin 4D (Sema4D) receptor Plexin-B1 directly stimulates the intrinsic guanosine triphosphatase (GTPase) activity of R-Ras, a member of the Ras superfamily of small GTP-binding proteins that has been implicated in promoting cell adhesion and neurite outgrowth [16].
  • Aberrancy produced via tryptophan depletion results in a different pattern of SEP distribution [4].
  • Within C. trachomatis-infected cells, ampicillin treatment leads to high levels of SEP accumulation at the periphery of aberrant RB, while in C. psittaci, treatment causes SEP to localize to distinct punctate sites within the bacteria [4].

Physical interactions of PLXNB1

  • In this study, we have identified two kinds of PDZ domain-containing Rho-specific guanine nucleotide exchange factors (RhoGEFs) as proteins interacting with plexin-B1 cytoplasmic domain [13].
  • 1H, 15N and 13C Resonance assignments and secondary structure determination reveal that the minimal Rac1 GTPase binding domain of plexin-B1 has a ubiquitin fold [17].

Regulatory relationships of PLXNB1


Other interactions of PLXNB1

  • We have also observed that the semaphorin CD100, a ligand for plexin-B1, stimulates the interaction between plexin-B1 and active Rac [19].
  • Rac specifically interacts with the cytosolic domain of plexin-B1, but not with that of plexin-A3 or -C1 [19].
  • Whereas c-Met, with which plexin-B1 can interact, is known to be a potent promoter of angiogenesis, the effects of semaphorin-mediated plexin activation in endothelial cells are still poorly understood [20].
  • The class 4 semaphorin CD100/Sema4D, which utilizes plexin-B1 and CD72 as receptors, exerts important biological effects on a variety of cells, including the neuronal, epithelial and immune cells [21].
  • The finding that nurselike cells from B-CLL patients express CD31 and plexin-B1, which deliver growth and survival signals to CD38+/CD100+ B-CLL cells, further confirms the model proposed [22].

Analytical, diagnostic and therapeutic context of PLXNB1

  • ABP and SEP may reveal a reversible component of the disease that cannot be detected by MRI, and may be a more sensitive measure of treatment efficacy [8].
  • Measures of wave-shape stability were computed for auditory (AEP) and somatosensory (SEP) evoked potentials, recorded from one EOG and 14 scalp leads [23].
  • Evoked potential studies of the somatosensory system with standard electrical stimulation (SEP) generally fail to establish objective correlates of such sensory deficits, because electrical stimuli predominantly activate large myelinated fibers that project into the medial lemniscal system [24].
  • The heptadecapeptide form the rabbit gastrin was extracted from 16 rabbit antra and purified by a combination of DEAE Sephadex, C-18 SEP PAK cartridges, fast performance liquid chromatography (FPLC) and reverse phase high pressure liquid chromatography (HPLC) steps [25].
  • The results of this study are of use for discrete and continuous PTN-SEP monitoring on intensive care units and during neuroradiological interventions and neurosurgery [5].


  1. Semaphorin 4D provides a link between axon guidance processes and tumor-induced angiogenesis. Basile, J.R., Castilho, R.M., Williams, V.P., Gutkind, J.S. Proc. Natl. Acad. Sci. U.S.A. (2006) [Pubmed]
  2. Ipsilateral hemiplegia caused by right internal capsule and thalamic hemorrhage: demonstration of predominant ipsilateral innervation of motor and sensory systems by MRI, MEP, and SEP. Hosokawa, S., Tsuji, S., Uozumi, T., Matsunaga, K., Toda, K., Ota, S. Neurology (1996) [Pubmed]
  3. Evoked potentials in motor system diseases. Cascino, G.D., Ring, S.R., King, P.J., Brown, R.H., Chiappa, K.H. Neurology (1988) [Pubmed]
  4. Identification of an antigen localized to an apparent septum within dividing chlamydiae. Brown, W.J., Rockey, D.D. Infect. Immun. (2000) [Pubmed]
  5. Inter- and intraindividual variability of posterior tibial nerve somatosensory evoked potentials in comatose patients. Adams, H.P., Kunz, S. Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society. (1996) [Pubmed]
  6. Increased central motor tract excitability in Creutzfeldt-Jakob disease. Yokota, T., Yoshino, A., Hirashima, F., Komori, T., Miyatake, T. J. Neurol. Sci. (1994) [Pubmed]
  7. R-Ras fills another GAP in semaphorin signalling. Pasterkamp, R.J. Trends Cell Biol. (2005) [Pubmed]
  8. Evoked potentials in assessment and follow-up of patients with Wilson's disease. Grimm, G., Oder, W., Prayer, L., Ferenci, P., Madl, C. Lancet (1990) [Pubmed]
  9. Plexin-B1/RhoGEF-mediated RhoA activation involves the receptor tyrosine kinase ErbB-2. Swiercz, J.M., Kuner, R., Offermanns, S. J. Cell Biol. (2004) [Pubmed]
  10. Plexin B regulates Rho through the guanine nucleotide exchange factors leukemia-associated Rho GEF (LARG) and PDZ-RhoGEF. Perrot, V., Vazquez-Prado, J., Gutkind, J.S. J. Biol. Chem. (2002) [Pubmed]
  11. A family of transmembrane proteins with homology to the MET-hepatocyte growth factor receptor. Maestrini, E., Tamagnone, L., Longati, P., Cremona, O., Gulisano, M., Bione, S., Tamanini, F., Neel, B.G., Toniolo, D., Comoglio, P.M. Proc. Natl. Acad. Sci. U.S.A. (1996) [Pubmed]
  12. Direct interaction of Rnd1 with Plexin-B1 regulates PDZ-RhoGEF-mediated Rho activation by Plexin-B1 and induces cell contraction in COS-7 cells. Oinuma, I., Katoh, H., Harada, A., Negishi, M. J. Biol. Chem. (2003) [Pubmed]
  13. Interaction of plexin-B1 with PDZ domain-containing Rho guanine nucleotide exchange factors. Hirotani, M., Ohoka, Y., Yamamoto, T., Nirasawa, H., Furuyama, T., Kogo, M., Matsuya, T., Inagaki, S. Biochem. Biophys. Res. Commun. (2002) [Pubmed]
  14. Semaphorin 4D/plexin-B1 induces endothelial cell migration through the activation of PYK2, Src, and the phosphatidylinositol 3-kinase-Akt pathway. Basile, J.R., Afkhami, T., Gutkind, J.S. Mol. Cell. Biol. (2005) [Pubmed]
  15. CD100/Plexin-B1 interactions sustain proliferation and survival of normal and leukemic CD5+ B lymphocytes. Granziero, L., Circosta, P., Scielzo, C., Frisaldi, E., Stella, S., Geuna, M., Giordano, S., Ghia, P., Caligaris-Cappio, F. Blood (2003) [Pubmed]
  16. The Semaphorin 4D receptor Plexin-B1 is a GTPase activating protein for R-Ras. Oinuma, I., Ishikawa, Y., Katoh, H., Negishi, M. Science (2004) [Pubmed]
  17. 1H, 15N and 13C Resonance assignments and secondary structure determination reveal that the minimal Rac1 GTPase binding domain of plexin-B1 has a ubiquitin fold. Tong, Y., Buck, M. J. Biomol. NMR (2005) [Pubmed]
  18. Plexin-B1 utilizes RhoA and Rho kinase to promote the integrin-dependent activation of Akt and ERK and endothelial cell motility. Basile, J.R., Gavard, J., Gutkind, J.S. J. Biol. Chem. (2007) [Pubmed]
  19. The semaphorin receptor plexin-B1 specifically interacts with active Rac in a ligand-dependent manner. Vikis, H.G., Li, W., He, Z., Guan, K.L. Proc. Natl. Acad. Sci. U.S.A. (2000) [Pubmed]
  20. Class IV semaphorins promote angiogenesis by stimulating Rho-initiated pathways through plexin-B. Basile, J.R., Barac, A., Zhu, T., Guan, K.L., Gutkind, J.S. Cancer Res. (2004) [Pubmed]
  21. Biological functions and signaling of a transmembrane semaphorin, CD100/Sema4D. Kumanogoh, A., Kikutani, H. Cell. Mol. Life Sci. (2004) [Pubmed]
  22. CD38 and CD100 lead a network of surface receptors relaying positive signals for B-CLL growth and survival. Deaglio, S., Vaisitti, T., Bergui, L., Bonello, L., Horenstein, A.L., Tamagnone, L., Boumsell, L., Malavasi, F. Blood (2005) [Pubmed]
  23. Somatosensory and auditory evoked potential studies of functional differences between the cerebral hemispheres in psychosis. Roemer, R.A., Shagass, C., Straumanis, J.J., Amadeo, M. Biol. Psychiatry (1979) [Pubmed]
  24. Recovery from brain-stem lesions involving the nociceptive pathways: comparison of clinical findings with laser-evoked potentials. Hansen, H.C., Treede, R.D., Lorenz, J., Kunze, K., Bromm, B. Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society. (1996) [Pubmed]
  25. Isolation and characterization of rabbit gastrin. Jiang, R., Huebner, V.D., Lee, T.D., Chew, P., Ho, F.J., Shively, J.E., Walsh, J.H., Reeve, J.R. Peptides (1988) [Pubmed]
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