Immunologically unique and common domains within a family of proteins related to the retina Ca2+-dependent cell adhesion molecule, NcalCAM

Abstract

Rabbit polyclonal antibodies raised to gp90, a fragment of the embryonic chick neural retina Ca²⁺dependent adhesive molecule, gp130, recognize gp130 and inhibit Ca²⁺-dependent cell-cell adhesion. When tested against a panel of 10-day embryonic tissues, one of these antisera recognizes a component with a molecular weight identical to that of gp130 in embryonic chick cerebrum, optic lobe, hind brain, spinal cord and neural retina only; the second antiserum recognizes a similar component in all of the embryonic chick tissues tested. These data imply the existence of an extended family of closely related cell surface components with immunologically distinct subgroups each of which may mediate Ca²⁺-dependent cell-cell adhesion. As the term CAM, or cell adhesion molecule, has become common usage we propose to refer to these molecules as calCAMs, reflecting their calcium dependence. Analysis of fragments and endoglycosidase digests of NcalCAM have allowed a comparison of its structure with similar molecules from different tissues and species that have been implicated in Ca²⁺-dependent cell-cell adhesion.