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Full-Text Articles in Medicine and Health Sciences
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 …
Identification By Peptide Analysis Of The Spectrin-Binding Protein In Human Erythrocytes, Elizabeth Luna, G. Kidd, D. Branton
Identification By Peptide Analysis Of The Spectrin-Binding Protein In Human Erythrocytes, Elizabeth Luna, G. Kidd, D. Branton
Elizabeth J. Luna
One-dimensional and two-dimensional peptide-mapping techniques are used to identify the protein which gives rise to the 72,000 dalton alpha-chymotryptic fragment previously shown to be the membrane attachment site for spectrin. Peptide maps of the 72,000 dalton fragment are very different from maps of Bands 1, 2, 2.9, 3, 3.1, 4.1, and 4.2 and very similar to maps of the apparently closely homologous polypeptides, Bands 2.1, 2.2, 2.3, and 2.6. Limited proteolysis of erythrocyte membranes is shown to generate Band 3', another polypeptide which has been associated with spectrin-binding activity. Peptide maps of Band 3' are very similar to maps of …
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 …
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.