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The Basement Membrane Protein BM-600/Nicein Codistributes with Kalinin and the Integrin α6β4 in Human Cultured Keratinocytes

1993; Elsevier BV; Volume: 205; Issue: 2 Linguagem: Inglês

10.1006/excr.1993.1078

1090-2422

P. C. Marchisio, Ottavio Cremona, Paola Savoia, Graziella Pellegrini, J.‐P. Ortonne, Patrick Verrando, Robert E. Burgeson, Ranieri Cancedda, Michele De Luca,

Glycosylation and Glycoproteins Research

The observation is reported that in low-passage human keratinocyte colonies cultured under conditions that allow full epidermal differentiation (i) the basement membrane protein BM-600/nicein, identified by the mAb GB3, is codistributed with laminin and collagen type IV as well as with the bullous pemphigoid antigen in footprints deposited by growing and migrating colonies; (ii) the integrin heterodimer α6β4 is codistributed with the same molecules suggesting its spatial association with basement membrane components; (iii) the distribution pattern of α6β4 and BM-600/nicein underneath individual cells is identical and is characterized by a typical "leopard skin" pattern complementary to the distribution of submembraneous F-actin microfilament network; (iv) a rabbit polyclonal antiserum to kalinin (R4012) used in double-label immunofluorescence staining with mAb GB3 shows that this protein has the same distribution as BM-600/nicein and this suggests that they are identically located; and (v) immunoprecipitation with mAb GB3 to BM-600/nicein and BM165 to kalinin shows identical bands suggesting that nicein and kalinin represent the same molecular entity. We suggest that α6β4 displays not only an adhesive role for keratinocytes in view of its reported association to hemidesmosomes but may also be involved in organizing the molecules of the epithelial extracellular matrix, including those forming the basement membrane zone and hemidesmosomes, a function proposed for other integrins in other cellular systems.