Release of the 120 kDa component of the mouse neural cell adhesion molecule N-CAM from cell surfaces by phosphatidylinositol-specific phospholipase C.

To study the membrane anchoring of the 120 kDa component of the neural cell adhesion molecule N-CAM, the smallest form lacking a transmembrane domain, cultured mouse neural cells were treated with phosphatidylinositol-specific phospholipase C from Staphylococcus aureus. When live cultures of astrocytes and neurons are treated with phosphatidylinositol-specific phospholipase C, N-CAM120 is released into the supernatant. Under these conditions N-CAM140 and N-CAM180 are not released. Phospholipase C from Bacillus cereus or Clostridium perfringens does not release N-CAM120. The embryonic form of N-CAM on astrocytes migrating as a broad band between 120 and 180 kDa is also partially released by phosphatidylinositol-specific phospholipase C as a band migrating between 120 and 160 kDa. These observations suggest novel mechanisms in regulation of N-CAM120 expression on the cell surface and in modulation of N-CAM-mediated cell adhesion.