Differential glycosylation and proteolytical processing of LeechCAM in central and peripheral leech neurons

LeechCAM is a recently described member of the Ig-superfamily which has fiv e Ig-domains, two FNIII-domains, a transmembrane domain, and a cytoplasmic domain. Phylogenetic analysis indicated that LeechCAM is the leech homolog of apCAM, FasII, and vertebrate NCAM. Using a leechCAM-specific monoclonal antibody we show by immunoblot analysis and by Triton X-114 phase separatio n experiments that in addition to existing in a transmembrane version Leech CAM is likely to be proteolytically cleaved into a secreted form without th e transmembrane domain and the intracellular tail. Furthermore, by immunopr ecipitation we demonstrate that LeechCAM is glycosylated with the Laz2-369 glycoepitope, an epitope that has been specifically implicated in regulatio n of axonal outgrowth and synapse formation. (C) 1999 Elsevier Science B.V. All rights reserved.