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Full-Text Articles in Cell Biology
Mutant Rac1b Expression In Dictyostelium: Effects On Morphology, Growth, Endocytosis, Development, And The Actin Cytoskeleton, S. Palmieri, Thomas Nebl, Robert Pope, D. Seastone, E. Lee, E. Hinchcliffe, Greenfield Sluder, D. Knecht, J. Cardelli, Elizabeth Luna
Mutant Rac1b Expression In Dictyostelium: Effects On Morphology, Growth, Endocytosis, Development, And The Actin Cytoskeleton, S. Palmieri, Thomas Nebl, Robert Pope, D. Seastone, E. Lee, E. Hinchcliffe, Greenfield Sluder, D. Knecht, J. Cardelli, Elizabeth Luna
Elizabeth J. Luna
Rac1 is a small G-protein in the Ras superfamily that has been implicated in the control of cell growth, adhesion, and the actin-based cytoskeleton. To investigate the role of Rac1 during motile processes, we have established Dictyostelium cell lines that conditionally overexpress epitope-tagged Dictyostelium discoideum wild-type Rac1B (DdRac1B) or a mutant DdRac1B protein. Expression of endogenous levels of myc- or GFP-tagged wild-type DdRac1B had minimal effect on cellular morphologies and behaviors. By contrast, expression of a constitutively active mutant (G12-->V or Q61-->L) or a dominant negative mutant (T17-->N) generated amoebae with characteristic cellular defects. The morphological appearance …
Merlin Differs From Moesin In Binding To F-Actin And In Its Intra- And Intermolecular Interactions, L. Huang, E. Ichimaru, Kersi Pestonjamasp, X. Cui, H. Nakamura, G. Lo, F. Lin, Elizabeth Luna, H. Furthmayr
Merlin Differs From Moesin In Binding To F-Actin And In Its Intra- And Intermolecular Interactions, L. Huang, E. Ichimaru, Kersi Pestonjamasp, X. Cui, H. Nakamura, G. Lo, F. Lin, Elizabeth Luna, H. Furthmayr
Elizabeth J. Luna
The neurofibromatosis type 2 (NF2) tumor suppressor gene encodes merlin, a protein with homology to the cell membrane/F-actin linking proteins, moesin, ezrin and radixin. Unlike these closely related proteins, merlin lacks a C-terminal F-actin binding site detectable by actin blot overlays, and the GFP-tagged merlin C-terminal domain co-distributes with neither stress fibers nor cortical actin in NIH3T3 cells. Merlin also differs from the other three proteins in its inter- and intramolecular domain interactions, as shown by in vitro binding and yeast two-hybrid assays. As is true for ezrin, moesin and radixin, the N- and C-terminal domains of merlin type 1 …
A Stable, High Capacity, F-Actin Affinity Column, Elizabeth Luna, Y. Wang, E. Voss, D. Branton, D. Taylor
A Stable, High Capacity, F-Actin Affinity Column, Elizabeth Luna, Y. Wang, E. Voss, D. Branton, D. Taylor
Elizabeth J. Luna
A high capacity F-actin affinity matrix is constructed by binding fluorescyl-actin to rabbit anti-fluorescein IgG that is covalently bound to Sepharose 4B. When stabilized with phalloidin, the actin remains associated with the Sepharose beads during repeated washes, activates the ATPase activity of myosin subfragment 1, and specifically binds 125I-heavy meromyosin and 125I-tropomyosin. The associations between the F-actin affinity matrix and the iodinated F-actin binding proteins are monitored both by affinity chromatography and by a rapid, low speed sedimentation assay. Anti-fluorescein IgG-Sepharose should be generally useful as a matrix for the immobilization of proteins containing accessible, covalently bound fluorescein groups.
F-Actin And Myosin Ii Binding Domains In Supervillin, Yu Chen, Norio Takizawa, Jessica Crowley, Sang Oh, Cheryl Gatto, Taketoshi Kambara, Osamu Sato, Xiang-Dong Li, Mitsuo Ikebe, Elizabeth Luna
F-Actin And Myosin Ii Binding Domains In Supervillin, Yu Chen, Norio Takizawa, Jessica Crowley, Sang Oh, Cheryl Gatto, Taketoshi Kambara, Osamu Sato, Xiang-Dong Li, Mitsuo Ikebe, Elizabeth Luna
Elizabeth J. Luna
Detergent-resistant membranes contain signaling and integral membrane proteins that organize cholesterol-rich domains called lipid rafts. A subset of these detergent-resistant membranes (DRM-H) exhibits a higher buoyant density ( approximately 1.16 g/ml) because of association with membrane skeleton proteins, including actin, myosin II, myosin 1G, fodrin, and an actin- and membrane-binding protein called supervillin (Nebl, T., Pestonjamasp, K. N., Leszyk, J. D., Crowley, J. L., Oh, S. W., and Luna, E. J. (2002) J. Biol. Chem. 277, 43399-43409). To characterize interactions among DRM-H cytoskeletal proteins, we investigated the binding partners of the novel supervillin N terminus, specifically amino acids 1-830. We …
Membrane Cytoskeleton: Pip(2) Pulls The Strings, Thomas Nebl, Sang Oh, Elizabeth Luna
Membrane Cytoskeleton: Pip(2) Pulls The Strings, Thomas Nebl, Sang Oh, Elizabeth Luna
Elizabeth J. Luna
A recent application of optical tweezers has shown that plasma membrane phosphatidylinositol 4,5-bisphosphate (PIP(2)) levels control adhesion of the membrane bilayer to the underlying cytoskeleton, by regulated direct binding of PIP(2) to cytoskeletal proteins and/or indirect effects on cytoskeleton structure.