CNP (CNPase) is a protein that comprises roughly 4% of total myelin in the central nervous system. It is thought to be involved in RNA metabolism in the myelinating cell as well as in oligodendrocyte differentiation. CNP regulates microtubule distribution in the cell cytoplasm and can catalyze microtubule formation in the brain and thyroid. In the injured brain, CNP functions in axonal maintenance and neuroprotection. Dysregulation and dysfunction of CNP is found in neurological, neurodegenerative and developmental syndromes including Alzheimer’s disease, Down’s syndrome, catatonia-depressive syndrome and potentially schizophrenia. It is also an auto-antigen in multiple sclerosis. In immunohistochemistry, CNP has high cytoplasmic and membranous positivity in oligodendrocytes in the brain and also in peripheral nerves. References: Journal of Neurochemistry. 69 (4): 1335–42, PMID: 9326261; Proceedings of the National Academy of Sciences of the United States of America. 99 (4): 1807–12. Bibcode:2002PNAS...99.1807B, PMID: 11842207; Neurosci Bull. 2014 Dec;30(6):956-966, PMID: 24807122