PROTEOLIPID PROTEIN - IS IT MORE THAN JUST A STRUCTURAL COMPONENT OF MYELIN

Proteolipid protein (PLP) is the most abundant protein of central nerv ous system (CNS) myelin. Because of its predicted topography, PLP has been assumed to function as a structural component of myelin, providin g stability and maintaining the compact lamellar structure. However, d evelopmental studies have shown that the PLP gene is active long befor e myelination begins, This and other evidence from various PLP mutants and transgenic models has fueled speculation that PLP or other produc ts of the gene have additional, nonstructural roles both within and ou tside the CNS. PLP is structurally related to a family of ion channel proteins which includes the connexins, synaptophysins and various neur otransmitter receptors, and there is some experimental evidence which supports a role for PLP in ion gating, Other provocative ideas are tha t the PLP gene may influence autocrine signaling within oligodendrocyt es or that PLP mRNAs have a function apart from protein coding.