Authors

L. M. Chen; D. Bailey;C. Fernandez-Valle

Comments

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Abbreviated Journal Title

J. Neurosci.

Keywords

Schwann cells; myelination; basal lamina; beta 1 integrin; focal; adhesion kinase; paxillin; tyrosine phosphorylation; signal transduction; TYROSINE PHOSPHORYLATION; SIGNAL-TRANSDUCTION; GENE-EXPRESSION; BASAL; LAMINA; EXTRACELLULAR-MATRIX; TRANSFORMED-CELLS; MYELIN FORMATION; LIM; DOMAINS; IN-VITRO; PROTEIN; Neurosciences

Abstract

Schwann cells (SCs) differentiate into a myelinating cell when simultaneously adhering to an axon destined for myelination and basal lamina. We are interested in defining the signaling pathway activated by basal lamina. Using SC/sensory neuron (N) cocultures, we identified beta 1 integrin and F-actin as components of a pathway leading to myelin gene expression and myelination (Fernandez-Valle et al., 1994, 1997). Here, we show that focal adhesion kinase (FAK) and paxillin are constitutively expressed by SCs contacting axons in the absence of basal lamina. Tyrosine phosphorylation of FAK and paxillin increases as SCs form basal lamina and differentiate. FAK and paxillin specifically coimmunoprecipitate with beta 1 integrin in differentiating SC/N cocultures but not SC-only cultures. Paxillin coimmunoprecipitates with FAK and fyn kinase in differentiating SC/N cocultures. A subset of tyrosine-phosphorylated b1 integrin, FAK, and paxillin molecules reside in the insoluble, F-actin-rich fraction of differentiating cocultures. Cytochalasin D, an actin depolymerizing agent, decreases tyrosine phosphorylation of FAK and paxillin and their association with b1 integrin and causes a dose-dependent increase in the abundance of insoluble FAK and paxillin complexes. Collectively, our work indicates that b1 integrin, FAK, paxillin, and fyn kinase form an actin-associated complex in SCs adhering to basal lamina in the presence of axons. This complex may be important for initiating the process of SC differentiation into a myelinating cell.

Journal Title

Journal of Neuroscience

Volume

20

Issue/Number

10

Publication Date

1-1-2000

Document Type

Article

Language

English

First Page

3776

Last Page

3784

WOS Identifier

WOS:000086940000032

ISSN

0270-6474

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