Calcium-activated neutral proteinase (calpain) has been extensively studied
over the past three decades such that many enzymatic and structural proper
ties of this enzyme are well understood. However, the pathophysiological ro
les of calpain remain poorly defined. In addition to recent studies delinea
ting a role for calpain in various pathological conditions, this proteinase
has been implicated in the degradation of myelin proteins in autoimmune de
myelinating diseases such as multiple sclerosis and experimental allergic e
ncephalomyelitis (EAE), In EAE, calpain translational expression is signifi
cantly increased in activated glial/inflammatory cells that participate in
myelinolysis while calpain substrates (axonal and myelin proteins) are lost
. Thus, since all major myelin proteins are calpain substrates, early studi
es suggest calpain may play an important role in demyelination of the centr
al nervous system. (C) 1999 Wiley-Liss, Inc.