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Title

Localization of focal adhesion kinase in differentiating Schwann cell/neuron cultures

Authors

Authors

C. Fernandez-Valle; P. M. Wood;M. B. Bunge

Comments

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Abbreviated Journal Title

Microsc. Res. Tech.

Keywords

Schwann cell; basal lamina; myelination; focal adhesion kinase; immunogold localization; SIGNAL-TRANSDUCTION; EXTRACELLULAR-MATRIX; BASAL LAMINA; TYROSINE; PHOSPHORYLATION; CELL MYELINATION; GENE-EXPRESSION; PROTEIN; INTEGRINS; INVITRO; BINDING; Anatomy & Morphology; Biology; Microscopy

Abstract

Previous studies have shown that Schwann cells (SCs) differentiate into myelin-forming or ensheathing cells only under conditions which allow the deposition of basal lamina and extracellular collagen [Bunge (1993) Peripheral Neuropathy, pp. 299-316]. SC adhesion to basal lamina is mediated by pi integrins and function blocking antibodies to pi integrins inhibit myelination [Fernandez-Valle et al. (1993) Development 119:867-880]. Recently, focal adhesion kinase (FAK), a cytoplasmic non-receptor tyrosine kinase, was found to mediate pi integrin-dependent signalling in a variety of cultured cell types adhering to ECM components such as fibronectin [reviewed in Schwartz et al. (1995) Ann. Rev. Cell Biol. 11:549-599; Ilic et al. (1997) J. Cell Sci. 110:401-407]. In the present study, we have determined more precisely the respective time courses of ECM deposition and myelination. In addition, we have studied by immunocytochemistry, immuno-gold labelling, and electron microscopy the expression and subcellular localization of FAK in nondifferentiating SCs and in SCs differentiating into myelinating cells. We show that the development of basal lamina and extracellular collagen fibrils precedes by 3 days the appearance of the first myelin sheaths. FAK was detected by immunocytochemistry or immune-gold labelling only in SCs differentiating in the presence of ascorbic acid. Localization of FAK to the abaxonal plasma membrane was dependent upon ECM deposition. Cytochalasin D did not prevent or disrupt localization of FAK to the plasma membrane. These data support the possibility that FAK acts as an intermediate in the pathway by. which basal lamina regulates SC differentiation. Microsc. Res. Tech. 41:416-430, 1998. (C) 1998 Wiley-Liss, Inc.

Journal Title

Microscopy Research and Technique

Volume

41

Issue/Number

5

Publication Date

1-1-1998

Document Type

Article

Language

English

First Page

416

Last Page

430

WOS Identifier

WOS:000074477000008

ISSN

1059-910X

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