{alpha}-Crystallin localizes to the leading edges of migrating lens epithelial cells
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710 (United States)
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710 (United States) and Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710 (United States)
{alpha}-crystallin ({alpha}A and {alpha}B) is a major lens protein, which belongs to the small heat-shock family of proteins and binds to various cytoskeletal proteins including actin, vimentin and desmin. In this study, we investigated the cellular localization of {alpha}A and {alpha}B-crystallins in migrating epithelial cells isolated from porcine lens. Immunofluorescence localization and confocal imaging of {alpha}B-crystallin in confluent and in migrating subconfluent cell cultures revealed a distinct pattern of subcellular distribution. While {alpha}B-crystallin localization was predominantly cytoplasmic in confluent cultures, it was strongly localized to the leading edges of cell membrane or the lamellipodia in migrating cells. In accordance with this pattern, we found abundant levels of {alpha}B-crystallin in membrane fractions compared to cytosolic and nuclear fractions in migrating lens epithelial cells. {alpha}A-crystallin, which has 60% sequence identity to {alpha}B-crystallin, also exhibited a distribution profile localizing to the leading edge of the cell membrane in migrating lens epithelial cells. Localization of {alpha}B-crystallin to the lamellipodia appears to be dependent on phosphorylation of residue serine-59. An inhibitor of p38 MAP kinase (SB202190), but not the ERK kinase inhibitor PD98059, was found to diminish localization of {alpha}B-crystallin to the lamellipodia, and this effect was found to be associated with reduced levels of Serine-59 phosphorylated {alpha}B-crystallin in SB202190-treated migrating lens epithelial cells. {alpha}B-crystallin localization to the lamellipodia was also altered by the treatment with RGD (Arg-Ala-Asp) peptide, dominant negative N17 Rac1 GTPase, cytochalasin D and Src kinase inhibitor (PP2), but not by the Rho kinase inhibitor Y-27632 or the myosin II inhibitor, blebbistatin. Additionally, in migrating lens epithelial cells, {alpha}B-crystallin exhibited a clear co-localization with the actin meshwork, {beta}-catenin, WAVE-1, a promoter of actin nucleation, Abi-2, a component of WAVE-1 protein complex and Arp3, a protein of the actin nucleation complex, suggesting potential interactions between {alpha}B-crystallin and regulatory proteins involved in actin dynamics and cell adhesion. This is the first report demonstrating specific localization of {alpha}A and {alpha}B-crystallins to the lamellipodia in migrating lens epithelial cells and our findings indicate a potential role for {alpha}-crystallin in actin dynamics during cell migration.
- OSTI ID:
- 20717605
- Journal Information:
- Experimental Cell Research, Vol. 306, Issue 1; Other Information: DOI: 10.1016/j.yexcr.2005.01.026; PII: S0014-4827(05)00040-6; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
- Country of Publication:
- United States
- Language:
- English
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