Characterization of lens fiber cell triton insoluble fraction reveals ERM (ezrin, radixin, moesin) proteins as major cytoskeletal-associated proteins.
To understand lens fiber cell elongation- and differentiation-associated cytoskeletal remodeling, here we identified and characterized the major protein components of lens fiber cell Triton X-100 insoluble fraction by mass spectrometry and immunoblot analysis. This analysis identified spectrin, filensin, vimentin, tubulin, phakinin, and beta-actin as major cytoskeletal proteins in the lens fibers. Importantly, ezrin, radixin, and moesin (ERM), heat-shock cognate protein 70, and beta/gamma-crystallins were identified as major cytoskeletal-associated proteins. ERM proteins were confirmed to exist as active phosphorylated forms that exhibited intense distribution in the organelle free-zone fibers. Furthermore, ERM protein phosphorylation was found to be dramatically reduced in Rho GTPase-targeted transgenic mouse lenses. These data identify the ERM proteins, which cross-link the plasma membrane and actin, as major and stable cytoskeletal-associated proteins in lens fibers, and indicate a potential role(s) for the ERMs in fiber cell actin cytoskeletal and membrane organization.
Rao
P Vasantha
PV
Department of Ophthalmology, Duke University School of Medicine, Box 3802, Durham, NC 27710, USA.
Ho
Tammy
T
Skiba
Nikolai P
NP
Maddala
Rupalatha
R
D000818:Animals; D002474:Cell-Free System; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D003599:Cytoskeleton / Q000737:chemistry / Q000378:metabolism*; D007908:Lens, Crystalline / Q000166:cytology* / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008840:Microfilament Proteins / Q000737:chemistry / Q000378:metabolism*; D017830:Octoxynol / Q000737:chemistry; D012995:Solubility; D000099149:Ezrin
D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D017830:Octoxynol; D000099149:Ezrin; C071058:moesin; C071776:radixin