NEUROSERPIN, AN AXONALLY SECRETED SERINE-PROTEASE INHIBITOR

We have identified and chromatographically purified an axonally secret ed glycoprotein of CNS and PNS neurons, Several peptides derived from it were microsequenced, Based on these sequences, a fragment of the co rresponding cDNA was amplified and used as a probe to isolate a full l ength cDNA from a chicken brain cDNA library. Because the deduced amin o acid sequence qualified the protein as a novel member of the serpin family of serine protease inhibitors, we called it neuroserpin, Analys is of the primary structural features further characterized neuroserpi n as a heparin-independent, functional inhibitor of a trypsinlike seri ne protease, In situ hybridization revealed a predominantly neuronal e xpression during the late stages of neurogenesis and in the adult brai n in regions which exhibit synaptic plasticity, Thus, neuroserpin migh t function as an axonally secreted regulator of the local extracellula r proteolysis involved in the reorganization of the synaptic connectiv ity during development and synapse plasticity in the adult.