Linda Amos - Academia.edu (original) (raw)
Papers by Linda Amos
Journal of Cell Science
Electron micrographs of outer doublet tubules from flagella have been analysed by methods which m... more Electron micrographs of outer doublet tubules from flagella have been analysed by methods which make use of the computed diffraction patterns of electron-microscope images. Analysis of singlet A-tubules in the tips of flagella has led to a determination of the helical surface lattice of the A-subfibre, confirming that there are 13 longitudinal protofilaments in the tubule wall and that dimers in neighbouring protofilaments form a staggered arrangement, equivalent to the lattice with an axial periodicity of 8-o nm predicted in earlier work. A low-resolution 3-dimensional image of the A-tubule has been reconstructed, which supports the evidence for an 80-nm-long heterodimer oriented along the protofilaments. The heterodimer is identified as a pair of 4'O-nm morphological units, which appear to be globular at this resolution.
Journal of Cell Science
Cytoplasmic dynein 'was purified from pig brain, using a modified version of published procedures... more Cytoplasmic dynein 'was purified from pig brain, using a modified version of published procedures, in order to study its interaction with microtubules. Since the preparation produces ATP-dependent sliding of taxol-stabilized purified microtubules over glass and runs on SDS-containing gels as a major band exceeding 300 000 M r plus a medium chain band at about 75 000 M r , it is assumed to be identical to the mammalian brain dynein (MAP 1C) purified by Vallee and colleagues.
Journal of Cell Science
Kinesin, a protein that transports particles along micro tubules, has been purified from pig brai... more Kinesin, a protein that transports particles along micro tubules, has been purified from pig brain, following published methods. By electron microscopy of both shadowed and negatively stained specimens, it appears to be a rod with a large branched structure at one end and a small fork at the other. The total length of the structure is about 100 nm. The rod has a diameter of 2-4 nm. Close to the middle of the rod there may be a flexible joint. The molecules appear to be attached to microtubules most often by their forked ends in the presence of AMP • PNP. However, the large branched end can also attach to microtubules and individual molecules occasionally have been seen cross-linking two microtubules.
Nature Cell Biology, 2000
Advances in Protein Chemistry, 2005
Microtubules are very dynamic polymers whose assembly and disassembly is determined by whether th... more Microtubules are very dynamic polymers whose assembly and disassembly is determined by whether their heterodimeric tubulin subunits are in a straight or curved conformation. Curvature is introduced by bending at the interfaces between monomers. Assembly and disassembly are primarily controlled by the hydrolysis of guanosine triphosphate (GTP) in a site that is completed by the association of two heterodimers. However, a multitude of associated proteins are able to fine-tune these dynamics so that microtubules are assembled and disassembled where and when they are required by the cell. We review the recent progress that has been made in obtaining a glimpse of the structural interactions involved.
The protein tubulin is the principal constituent of microtubules, whose dynamic behaviour allows ... more The protein tubulin is the principal constituent of microtubules, whose dynamic behaviour allows them to perform a vital role in various forms of cell motility. Found in almost all types of eukaryotic cell, microtubules are an essential component of cell division, provide tracks for the transport of cellular organelles and vesicles and are responsible for the relative positioning of cellular compartments.
Protein family review T Th he e t te ek kt ti in n f fa am mi il ly y o of f m mi ic cr ro ot tu ... more Protein family review T Th he e t te ek kt ti in n f fa am mi il ly y o of f m mi ic cr ro ot tu ub bu ul le e--s st ta ab bi il li iz zi in ng g p pr ro ot te ei in ns s
Trends in Cell Biology, 2004
Trends in Cell Biology, 1995
In 1974, optical diffraction and image analysis indicated that tubulin dimers in the cylindricall... more In 1974, optical diffraction and image analysis indicated that tubulin dimers in the cylindrically complete A-tubule of flagellar doublet microtubules are arranged with helical symmetry, while those in the incomplete B-tubule associate differently. Recently, electron micrographs of reassembled brain microtubules decorated with kinesin heads have shown that the tubulin dimers there are arranged as in the B-tubule. The lack of symmetry of microtubules assembled in vitro prompts Linda Amos to speculate here that the assembly process in vitro may differ from that occurring in the cell.
The Journal of Cell Biology, 1977
The arrangement of the high molecular weight proteins associated with the walls of reconstituted ... more The arrangement of the high molecular weight proteins associated with the walls of reconstituted mammalian brain microtubules has been investigated by electron microscopy of negatively stained preparations. The images are found to be consistent with an arrangement whereby the high molecular weight molecules are spaced 12 tubulin dimers apart, i.e., 960 A,, along each protofilament of the microtubule, in agreement with the relative stoichiometry of tubulin and high molecular weight protein. Molecules on neighbouring protofilaments seem to be staggered so that they give rise to a helical superlattice, which can be superimposed on the underlying tubulin lattice. In micrographs of disintegrating tubules there is some indication of lateral interactions between neighbouring high molecular weight molecules.
Seminars in Cell & Developmental Biology, 2011
A wide range of small molecules, including alkaloids, macrolides and peptides, bind to tubulin an... more A wide range of small molecules, including alkaloids, macrolides and peptides, bind to tubulin and disturb microtubule assembly dynamics. Some agents inhibit assembly, others inhibit disassembly. The binding sites of drugs that stabilize microtubules are discussed in relation to the properties of microtubule associated proteins. The activities of assembly inhibitors are discussed in relation to different nucleotide states of tubulin family protein structures.
Science, 2008
Interstrand sliding (4). A MTBD with a distinct polarity (shown as a frog) and an antiparallel co... more Interstrand sliding (4). A MTBD with a distinct polarity (shown as a frog) and an antiparallel coiledcoil stalk in two conformations; the blue and green strands are shown sliding over each other.
Nature Chemical Biology, 2005
closure are themselves sensed by the channel gate, using parallel kinetic and electrophysiologica... more closure are themselves sensed by the channel gate, using parallel kinetic and electrophysiological analysis of mutants that affect the individual docking steps. Either way, the processes observed by Jayaraman and colleagues are likely to have important consequences for our understanding of the kinetics of binding and gating interactions in this physiologically important family of ion channels.
Journal of Cell Science
Electron micrographs of outer doublet tubules from flagella have been analysed by methods which m... more Electron micrographs of outer doublet tubules from flagella have been analysed by methods which make use of the computed diffraction patterns of electron-microscope images. Analysis of singlet A-tubules in the tips of flagella has led to a determination of the helical surface lattice of the A-subfibre, confirming that there are 13 longitudinal protofilaments in the tubule wall and that dimers in neighbouring protofilaments form a staggered arrangement, equivalent to the lattice with an axial periodicity of 8-o nm predicted in earlier work. A low-resolution 3-dimensional image of the A-tubule has been reconstructed, which supports the evidence for an 80-nm-long heterodimer oriented along the protofilaments. The heterodimer is identified as a pair of 4'O-nm morphological units, which appear to be globular at this resolution.
Journal of Cell Science
Cytoplasmic dynein 'was purified from pig brain, using a modified version of published procedures... more Cytoplasmic dynein 'was purified from pig brain, using a modified version of published procedures, in order to study its interaction with microtubules. Since the preparation produces ATP-dependent sliding of taxol-stabilized purified microtubules over glass and runs on SDS-containing gels as a major band exceeding 300 000 M r plus a medium chain band at about 75 000 M r , it is assumed to be identical to the mammalian brain dynein (MAP 1C) purified by Vallee and colleagues.
Journal of Cell Science
Kinesin, a protein that transports particles along micro tubules, has been purified from pig brai... more Kinesin, a protein that transports particles along micro tubules, has been purified from pig brain, following published methods. By electron microscopy of both shadowed and negatively stained specimens, it appears to be a rod with a large branched structure at one end and a small fork at the other. The total length of the structure is about 100 nm. The rod has a diameter of 2-4 nm. Close to the middle of the rod there may be a flexible joint. The molecules appear to be attached to microtubules most often by their forked ends in the presence of AMP • PNP. However, the large branched end can also attach to microtubules and individual molecules occasionally have been seen cross-linking two microtubules.
Nature Cell Biology, 2000
Advances in Protein Chemistry, 2005
Microtubules are very dynamic polymers whose assembly and disassembly is determined by whether th... more Microtubules are very dynamic polymers whose assembly and disassembly is determined by whether their heterodimeric tubulin subunits are in a straight or curved conformation. Curvature is introduced by bending at the interfaces between monomers. Assembly and disassembly are primarily controlled by the hydrolysis of guanosine triphosphate (GTP) in a site that is completed by the association of two heterodimers. However, a multitude of associated proteins are able to fine-tune these dynamics so that microtubules are assembled and disassembled where and when they are required by the cell. We review the recent progress that has been made in obtaining a glimpse of the structural interactions involved.
The protein tubulin is the principal constituent of microtubules, whose dynamic behaviour allows ... more The protein tubulin is the principal constituent of microtubules, whose dynamic behaviour allows them to perform a vital role in various forms of cell motility. Found in almost all types of eukaryotic cell, microtubules are an essential component of cell division, provide tracks for the transport of cellular organelles and vesicles and are responsible for the relative positioning of cellular compartments.
Protein family review T Th he e t te ek kt ti in n f fa am mi il ly y o of f m mi ic cr ro ot tu ... more Protein family review T Th he e t te ek kt ti in n f fa am mi il ly y o of f m mi ic cr ro ot tu ub bu ul le e--s st ta ab bi il li iz zi in ng g p pr ro ot te ei in ns s
Trends in Cell Biology, 2004
Trends in Cell Biology, 1995
In 1974, optical diffraction and image analysis indicated that tubulin dimers in the cylindricall... more In 1974, optical diffraction and image analysis indicated that tubulin dimers in the cylindrically complete A-tubule of flagellar doublet microtubules are arranged with helical symmetry, while those in the incomplete B-tubule associate differently. Recently, electron micrographs of reassembled brain microtubules decorated with kinesin heads have shown that the tubulin dimers there are arranged as in the B-tubule. The lack of symmetry of microtubules assembled in vitro prompts Linda Amos to speculate here that the assembly process in vitro may differ from that occurring in the cell.
The Journal of Cell Biology, 1977
The arrangement of the high molecular weight proteins associated with the walls of reconstituted ... more The arrangement of the high molecular weight proteins associated with the walls of reconstituted mammalian brain microtubules has been investigated by electron microscopy of negatively stained preparations. The images are found to be consistent with an arrangement whereby the high molecular weight molecules are spaced 12 tubulin dimers apart, i.e., 960 A,, along each protofilament of the microtubule, in agreement with the relative stoichiometry of tubulin and high molecular weight protein. Molecules on neighbouring protofilaments seem to be staggered so that they give rise to a helical superlattice, which can be superimposed on the underlying tubulin lattice. In micrographs of disintegrating tubules there is some indication of lateral interactions between neighbouring high molecular weight molecules.
Seminars in Cell & Developmental Biology, 2011
A wide range of small molecules, including alkaloids, macrolides and peptides, bind to tubulin an... more A wide range of small molecules, including alkaloids, macrolides and peptides, bind to tubulin and disturb microtubule assembly dynamics. Some agents inhibit assembly, others inhibit disassembly. The binding sites of drugs that stabilize microtubules are discussed in relation to the properties of microtubule associated proteins. The activities of assembly inhibitors are discussed in relation to different nucleotide states of tubulin family protein structures.
Science, 2008
Interstrand sliding (4). A MTBD with a distinct polarity (shown as a frog) and an antiparallel co... more Interstrand sliding (4). A MTBD with a distinct polarity (shown as a frog) and an antiparallel coiledcoil stalk in two conformations; the blue and green strands are shown sliding over each other.
Nature Chemical Biology, 2005
closure are themselves sensed by the channel gate, using parallel kinetic and electrophysiologica... more closure are themselves sensed by the channel gate, using parallel kinetic and electrophysiological analysis of mutants that affect the individual docking steps. Either way, the processes observed by Jayaraman and colleagues are likely to have important consequences for our understanding of the kinetics of binding and gating interactions in this physiologically important family of ion channels.