Trio in Myelin Nogo, Mag, and Omgp

named by Martin Schwab of Zurich University, is a member of the endoplasmic reticulum associated protein family, reticulon. Despite being associated with endoplasmic reticulum of oligodendrocytes, Nogo-A is also exhibited on the surface and mediates growth cone collapse (Fournier et al., 2002). 

Myelin-associated glycoprotein (Mag), belonging to immunoglobulin superfamily, is a potent inhibitor of post-mitotic neuronal outgrowth. There are two isoforms of this inhibitor that differ only in their cytoplasmic domain. Ability of Mag to bind sialic acid, although not essential for its inhibitory effect, potentiates it nonetheless (De Bellard and Filbin, 1999). 

In addition to myelin, inhibitory signals also arise from glial scars. Proteoglycans are the main culprit in this regard. Additionally, certain proteins present in the scar, like ephrin-B2 and Sema3, also repel the growth cone (Silver and Miller, 2004). 

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