Lb. Spiryda et Dr. Colman, PROTEIN ZERO, A MYELIN IGCAM, INDUCES PHYSIOLOGICALLY OPERATIVE TIGHTJUNCTIONS IN NONADHESIVE CARCINOMA-CELLS, Journal of neuroscience research, 54(2), 1998, pp. 282-288
In the peripheral nervous system, protein zero (P-0), a hemophilic imm
unoglubulin cell adhesion molecule, mediates adhesion of Schwann cell
membranes as they enwrap axons and generate compact myelin. Although P
o is naturally only expressed in peripheral myelin, it can behave as a
vigorous adhesion molecule in a variety of cell types (Filbin et al,
[1990] Nature 344:871-872; Schneider-Schaulies et al, [1990] J Neurosc
i Res 27:286-297; Doyle et al, [1995] J Cell Biol 131:465-482) and can
thus be characterized as an obligatory adhesion molecule, Previously,
we showed that when HeLa, a cervical carcinoma cell line devoid of ep
ithelial junctions, is forced to express P-0, strong cell-cell adhesio
n is induced, proteins associated with junctional elements are upregul
ated, and ultrastructurally tight junctions, adherens junctions, and d
esmosomes become apparent (Doyle et al,, 1995), In this report, we ass
essed whether the tight junctions were physiologically operative in P-
0 HeLa expressors. Consistent with the presence of operative light jun
ctions, me found that P-0 expressors in monolayers maintained endogeno
us proteins in their apical and basolateral plasma membrane subdomains
, Furthermore, these cells generated a higher transepithelial resistan
ce than did control HeLa cells, which is indicative of the formation o
f an effective intercellular permeability barrier (C) 1998 Wiley-Liss,
Inc.