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Formation of a β 1 integrin signaling complex in Schwann cells is independent of rho
Author(s) -
Taylor Anna R.,
Geden Sandra E.,
FernandezValle Cristina
Publication year - 2003
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.10170
Subject(s) - focal adhesion , paxillin , microbiology and biotechnology , biology , filopodia , integrin , basal lamina , ptk2 , signal transduction , receptor , anatomy , actin , protein kinase c , biochemistry , mitogen activated protein kinase kinase , ultrastructure
Schwann cell adhesion to basal lamina is essential for peripheral nerve development. β 1 integrin receptors for extracellular matrix cooperate with other receptors to transmit signals that coordinate cell cycle progression and initiation of differentiation, including myelin‐specific gene expression. In Schwann cell/sensory neuron cocultures, β 1 integrins complex with focal adhesion kinase (FAK), fyn kinase, paxillin, and schwannomin in response to basal lamina adhesion. To study the assembly of this signaling complex in Schwann cells (SCs), we induced β 1 integrin clustering on suspended cells using an immobilized antibody and recovered a complex containing β 1 integrin, FAK, paxillin, and schwannomin. In adherent subconfluent cells, the proteins colocalized to filopodia, ruffling membranes and focal contacts. We assessed the role of rhoGTPase in the process of integrin complex assembly by introducing C3 transferase (C3T), a rho inhibitor, into the cells. Although C3T caused dose‐dependent morphological abnormalities, FAK, paxillin, and schwannomin were able to coimmunoprecipitate with β 1 integrin. Additionally, colocalization of FAK, paxillin, and schwannomin with β 1 integrin in filopodia and small focal contacts remained unchanged. We conclude that SCs do not require active rho to recruit signaling and structural proteins to β 1 integrins clustered at the plasma membrane. Rho is required to establish large focal adhesions and to spread and stabilize plasma membrane extensions. GLIA 41:94–104, 2003. © 2003 Wiley‐Liss, Inc.