Characterization of β1 Integrin Cytoplasmic Domain Binding Proteins

Article Chronology:Received 28 March 2006Revised version received6 June 2006Accepted 13 June 2006Available online 29 June 2006The three Kindlins are a novel family of focal adhesion proteins. The Kindlin-1 (URP1) gene ismutated in Kindler syndrome, the first skin blistering disease affecting actin attachment inbasal keratinocytes. Kindlin-2 (Mig-2), the best studied member of this family, binds ILK andMigfilin, which links Kindlin-2 to the actin cytoskeleton. Kindlin-3 is expressed inhematopoietic cells. Here we describe the genomic organization, gene expression andsubcellular localization of murine Kindlins-1 to -3. In situ hybridizations showed thatKindlin-1 is preferentially expressed in epithelia, and Kindlin-2 in striated and smoothmuscle cells. Kindlins-1 and -2 are both expressed in the epidermis. While both localize tointegrin-mediated adhesion sites in cultured keratinocytes Kindlin-2, but not Kindlin-1,colocalizes with E-cadherin to cell-cell contacts in differentiated keratinocytes. Using aKindlin-3-specific antiserum and an EGFP-tagged Kindlin-3 construct, we could show thatKindlin-3 is present in the F-actin surrounding ring structure of podosomes, which arespecialized adhesion structures of hematopoietic cells.© 2006 Elsevier Inc. All rights reserved.