Integrin β4 Regulates Migratory Behavior of Keratinocytes by Determining Laminin-332 Organization

M. Peter Marinkovich,Teng-Leong Chew,Jessica N. Claiborne,Bernd U. Sehgal,Jonathan C.R. Jones,Susan B. Hopkinson,Alan Russell,Sumio Matzno,Phillip J. DeBiase

doi:10.1074/jbc.m606317200

Abstract

Whether alpha6beta4 integrin regulates migration remains controversial. beta4 integrin-deficient (JEB) keratinocytes display aberrant migration in that they move in circles, a behavior that mirrors the circular arrays of laminin (LM)-332 in their matrix. In contrast, wild-type keratinocytes and JEB keratinocytes, induced to express beta4 integrin, assemble laminin-332 in linear tracks over which they migrate. Moreover, laminin-332-dependent migration of JEB keratinocytes along linear tracks is restored when cells are plated on wild-type keratinocyte matrix, whereas wild-type keratinocytes show rotation over circular arrays of laminn-332 in JEB keratinocyte matrix. The activities of Rac1 and the actin cytoskeleton-severing protein cofilin are low in JEB keratinocytes compared with wild-type cells but are rescued following expression of wild-type beta4 integrin in JEB cells. Additionally, in wild-type keratinocytes Rac1 is complexed with alpha6beta4 integrin. Moreover, Rac1 or cofilin inactivation induces wild-type keratinocytes to move in circles over rings of laminin-332 in their matrix. Together these data indicate that laminin-332 matrix organization is determined by the alpha6beta4 integrin/actin cytoskeleton via Rac1/cofilin signaling. Furthermore, our results imply that the organizational state of laminin-332 is a key determinant of the motility behavior of keratinocytes, an essential element of skin wound healing and the successful invasion of epidermal-derived tumor cells.

Highlights

Migration of cells is an essential element of morphogenesis, remodeling following tissue damage and metastasis
These contradictory functions exhibited by LM-332, adhesion and motility, have been investigated by a number of laboratories, and results to date indicate that proteolytic processing of LM-332 has a profound impact on its functions
Control immunoglobulins had no apparent effect on migration. These results indicate that the motility of all of our assayed keratinocytes is likely growth factor- and ␣3␤1 integrin-regulated, consistent with previous studies [16, 36]

Summary

Introduction

Migration of cells is an essential element of morphogenesis, remodeling following tissue damage and metastasis. Wild-type keratinocytes and JEB keratinocytes, induced to express ␤4 integrin, assemble laminin-332 in linear tracks over which they migrate. Motility of Keratinocytes data indicate that ␣6␤4 integrin, through interaction with the Rac1 signaling pathway, regulates LM-332 matrix organization which, in turn, specifies patterns of cell motility.

Results

Conclusion