SEMA4G explained

Semaphorin-4G is a protein in humans encoded by the SEMA4G gene.^[1]

Semaphorins are a large family of conserved, secreted and membrane associated proteins which possess a semaphoring (Sema) domain and a PSI domain (found in plexins, semaphorins and integrins) in the N-terminal extracellular portion. Semaphorins maintain cell motility and attachment in axon guidance, immune cell maintenance, vascular growth and tumour movement.^[2]

Based on sequence and structural similarities, semaphorins are put into eight classes: invertebrates contain classes 1 and 2, viruses have class V, and vertebrates contain classes 3-7. Semaphorins serve as axon guidance ligands via multimeric receptor complexes, some (if not all) containing plexin proteins. This gene encodes a class 4 semaphorin. This gene and the gene for mitochondrial ribosomal protein L43 overlap at map location 10q24.31 and are transcribed in opposite directions.

Further reading

• Pasterkamp RJ, Kolodkin AL . Semaphorin junction: making tracks toward neural connectivity . Curr. Opin. Neurobiol. . 13 . 1 . 79–89 . 2003 . 12593985 . 10.1016/S0959-4388(03)00003-5 . 40661992 .
• Dickson BJ . Molecular mechanisms of axon guidance . Science . 298 . 5600 . 1959–64 . 2003 . 12471249 . 10.1126/science.1072165 . 28328792 .
• Book: Holtmaat AJ, De Winter F, De Wit J, etal . Semaphorins: Contributors to structural stability of hippocampal networks? . Plasticity in the Adult Brain: From Genes to Neurotherapy . Prog. Brain Res. . 138 . 17–38 . 2002 . 12432760 . 10.1016/S0079-6123(02)38068-3 . Progress in Brain Research . 978-0-444-50981-9 .
• Rual JF, Venkatesan K, Hao T, etal . Towards a proteome-scale map of the human protein-protein interaction network . Nature . 437 . 7062 . 1173–8 . 2005 . 16189514 . 10.1038/nature04209 . 2005Natur.437.1173R . 4427026 .
• Gerhard DS, Wagner L, Feingold EA, etal . The Status, Quality, and Expansion of the NIH Full-Length cDNA Project: The Mammalian Gene Collection (MGC) . Genome Res. . 14 . 10B . 2121–7 . 2004 . 15489334 . 10.1101/gr.2596504 . 528928 .
• Deloukas P, Earthrowl ME, Grafham DV, etal . The DNA sequence and comparative analysis of human chromosome 10 . Nature . 429 . 6990 . 375–81 . 2004 . 15164054 . 10.1038/nature02462 . 2004Natur.429..375D . free .
• Strausberg RL, Feingold EA, Grouse LH, etal . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–903 . 2003 . 12477932 . 10.1073/pnas.242603899 . 139241 . 2002PNAS...9916899M . free .
• Nagase T, Kikuno R, Nakayama M, etal . Prediction of the coding sequences of unidentified human genes. XVIII. The complete sequences of 100 new cDNA clones from brain which code for large proteins in vitro . DNA Res. . 7 . 4 . 273–81 . 2001 . 10997877 . 10.1093/dnares/7.4.271. free .

Notes and References

1. Web site: Entrez Gene: SEMA4G sema domain, immunoglobulin domain (Ig), transmembrane domain (TM) and short cytoplasmic domain, (semaphorin) 4G.
2. Kruger . Robert P. . Aurandt . Jennifer . Guan . Kun-Liang . October 2005 . Semaphorins command cells to move . Nature Reviews Molecular Cell Biology . en . 6 . 10 . 789–800 . 10.1038/nrm1740 . 1471-0080.