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Chris P Ponting - One of the best experts on this subject based on the ideXlab platform.

  • a new sequence motif linking lissencephaly treacher collins and oral facial digital type 1 syndromes microtubule dynamics and cell migration
    Human Molecular Genetics, 2001
    Co-Authors: Richard D Emes, Chris P Ponting
    Abstract:

    : A previously unidentified sequence motif has been identified in the products of genes mutated in Miller-Dieker lissencephaly, Treacher Collins, oral-facial-digital type 1 and contiguous syndrome ocular albinism with late onset sensorineural deafness syndromes. An additional homologous motif was detected in a gene product fused to the fibroblast growth factor receptor type 1 in patients with an atypical stem cell myeloproliferative disorder. In total, over 100 eukaryotic intracellular proteins are shown to possess a LIS1 homology (LisH) motif, including several katanin p60 subunits, muskelin, tonneau, LEUNIG, Nopp140, aimless and numerous WD repeat-containing Beta-Propeller proteins. It is suggested that LisH motifs contribute to the regulation of microtubule dynamics, either by mediating dimerization, or else by binding cytoplasmic dynein heavy chain or microtubules directly. The predicted secondary structure of LisH motifs, and their occurrence in homologues of Gbeta Beta-Propeller subunits, suggests that they are analogues of Ggamma subunits, and might associate with the periphery of Beta-Propeller domains. The finding of LisH motifs in both treacle and Nopp140 reinforces previous observations of functional similarities between these nucleolar proteins. Uncharacterized LisH motif-containing proteins represent candidates for other diseases associated with aberrant microtubule dynamics and defects of cell migration, nucleokinesis or chromosome segregation.

  • a new sequence motif linking lissencephaly treacher collins and oral facial digital type 1 syndromes microtubule dynamics and cell migration
    Human Molecular Genetics, 2001
    Co-Authors: Richard D Emes, Chris P Ponting
    Abstract:

    A previously unidentified sequence motif has been identified in the products of genes mutated in Miller-Dieker lissencephaly, Treacher Collins, oral-facial-digital type 1 and contiguous syndrome ocular albinism with late onset sensorineural deafness syndromes. An additional homologous motif was detected in a gene product fused to the fibroblast growth factor receptor type 1 in patients with an atypical stem cell myeloproliferative disorder. In total, over 100 eukaryotic intracellular proteins are shown to possess a LIS1 homology (LisH) motif, including several katanin p60 subunits, muskelin, tonneau, LEUNIG, Nopp140, aimless and numerous WD repeat-containing Beta-Propeller proteins. It is suggested that LisH motifs contribute to the regulation of microtubule dynamics, either by mediating dimerization, or else by binding cytoplasmic dynein heavy chain or microtubules directly. The predicted secondary structure of LisH motifs, and their occurrence in homologues of Gbeta Beta-Propeller subunits, suggests that they are analogues of Ggamma subunits, and might associate with the periphery of Beta-Propeller domains. The finding of LisH motifs in both treacle and Nopp140 reinforces previous observations of functional similarities between these nucleolar proteins. Uncharacterized LisH motif-containing proteins represent candidates for other diseases associated with aberrant microtubule dynamics and defects of cell migration, nucleokinesis or chromosome segregation.

Anne Imberty - One of the best experts on this subject based on the ideXlab platform.

  • The fucose-binding lectin from Ralstonia solanacearum. A new type of Beta-Propeller architecture formed by oligomerization and interacting with fucoside, fucosyllactose, and plant xyloglucan.
    Journal of Biological Chemistry, 2005
    Co-Authors: Nikola Kostlanova, Martina Lahmann, Stefan Oscarson, Nechama Gilboa-garber, Hugues Lortat-jacob, Edward P Mitchell, Michaela Wimmerova, Gérard Chambat, Anne Imberty
    Abstract:

    Plant pathogens, like animal ones, use protein-carbohydrate interactions in their strategy for host recognition, attachment, and invasion. The bacterium Ralstonia solanacearum, which is distributed worldwide and causes lethal wilt in many agricultural crops, was shown to produce a potent L-fucose-binding lectin, R. solanacearum lectin, a small protein of 90 amino acids with a tandem repeat in its amino acid sequence. In the present study, surface plasmon resonance experiments conducted on a series of oligosaccharides show a preference for binding to alphaFuc1-2Gal and alphaFuc1-6Gal epitopes. Titration microcalorimetry demonstrates the presence of two binding sites per monomer and an unusually high affinity of the lectin for alphaFuc1-2Gal-containing oligosaccharides (KD = 2.5 x 10(-7) M for 2-fucosyllactose). R. solanacearum lectin has been crystallized with a methyl derivative of fucose and with the highest affinity ligand, 2-fucosyllactose. X-ray crystal structures, the one with alpha-methyl-fucoside being at ultrahigh resolution, reveal that each monomer consists of two small four-stranded anti-parallel beta-sheets. Trimerization through a 3-fold or pseudo-3-fold axis generates a six-bladed Beta-Propeller architecture, very similar to that previously described for the fungal lectin of Aleuria aurantia. This is the first report of a Beta-Propeller formed by oligomerization and not by sequential domains. Each monomer presents two fucose binding sites, resulting in six symmetrically arranged sugar binding sites for the Beta-Propeller. Crystals were also obtained for a mutated lectin complexed with a fragment of xyloglucan, a fucosylated polysaccharide from the primary cell wall of plants, which may be the biological target of the lectin.

  • crystal structure of fungal lectin six bladed β propeller fold and novel fucose recognition mode for aleuria aurantia lectin
    Journal of Biological Chemistry, 2003
    Co-Authors: Michaela Wimmerova, Jeanfrederic Sanchez, Catherine Gautier, Edward P Mitchell, Anne Imberty
    Abstract:

    Aleuria aurantia lectin is a fungal protein composed of two identical 312-amino acid subunits that specifically recognizes fucosylated glycans. The crystal structure of the lectin complexed with fucose reveals that each monomer consists of a six-bladed Beta-Propeller fold and of a small antiparallel two-stranded beta-sheet that plays a role in dimerization. Five fucose residues were located in binding pockets between the adjacent propeller blades. Due to repeats in the amino acid sequence, there are strong similarities between the sites. Oxygen atoms O-3, O-4, and O-5 of fucose are involved in hydrogen bonds with side chains of amino acids conserved in all repeats, whereas O-1 and O-2 interact with a large number of water molecules. The nonpolar face of each fucose residue is stacked against the aromatic ring of a Trp or Tyr amino acid, and the methyl group is located in a highly hydrophobic pocket. Depending on the precise binding site geometry, the alpha- or beta-anomer of the fucose ligand is observed bound in the crystal. Surface plasmon resonance experiments conducted on a series of oligosaccharides confirm the broad specificity of the lectin, with a slight preference for alphaFuc1-2Gal disaccharide. This multivalent carbohydrate recognition fold is a new prototype of lectins that is proposed to be involved in the host recognition strategy of several pathogenic organisms including not only the fungi Aspergillus but also the phytopathogenic bacterium Ralstonia solanacearum.

  • six bladed s propeller fold and novel fucose recognition modefor aleuria aurantia lectin
    Journal of Biological Chemistry, 2003
    Co-Authors: Michaela Wimmerova, Jeanfrederick Sanchez, Catherine Gautier, Edward P Mitchell, Anne Imberty
    Abstract:

    Aleuria aurantia lectin is a fungal protein composed of two identical 312-amino acid subunits that specifically recognizes fucosylated glycans. The crystal structure of the lectin complexed with fucose reveals that each monomer consists of a six-bladed Beta-Propeller fold and of a small antiparallel two-stranded beta-sheet that plays a role in dimerization. Five fucose residues were located in binding pockets between the adjacent propeller blades. Due to repeats in the amino acid sequence, there are strong similarities between the sites. Oxygen atoms O-3, O-4, and O-5 of fucose are involved in hydrogen bonds with side chains of amino acids conserved in all repeats, whereas O-1 and O-2 interact with a large number of water molecules. The nonpolar face of each fucose residue is stacked against the aromatic ring of a Trp or Tyr amino acid, and the methyl group is located in a highly hydrophobic pocket. Depending on the precise binding site geometry, the alpha-or beta-anomer of the fucose ligand is observed bound in the crystal. Surface plasmon resonance experiments conducted on a series of oligosaccharides confirm the broad specificity of the lectin, with a slight preference for alpha-Fuc1-2Gal disaccharide. This multivalent carbohydrate recognition fold is a new prototype of lectins that is proposed to be involved in the host recognition strategy of several pathogenic organisms including not only the fungi Aspergillus but also the phytopathogenic bacterium Ralstonia solanacearum.

Michaela Wimmerova - One of the best experts on this subject based on the ideXlab platform.

  • a novel fucose binding lectin from photorhabdus luminescens pll with an unusual heptabladed β propeller tetrameric structure
    Journal of Biological Chemistry, 2016
    Co-Authors: Atul Kumar, Petra Sýkorova, Gabriel Demo, Pavel Dobes, Pavel Hyrsl, Michaela Wimmerova
    Abstract:

    Photorhabdus luminescens is known for its symbiosis with the entomopathogenic nematode Heterorhabditis bacteriophora and its pathogenicity toward insect larvae. Ahypothetical protein from P. luminescens was identified, purified from the native source, and characterized as an L-fucose-binding lectin, named P. luminescens lectin (PLL). Glycan array and biochemical characterization data revealed PLL to be specific toward L-fucose and the disaccharide glycan 3,6-O-Me-2-Glc beta 1-4(2,3-O-Me-2)Rha alpha-O-(p-C6H4)-OCH2CH2NH2. PLL was discovered to be a homotetramer with an intersubunit disulfide bridge. The crystal structures of native and recombinant PLL revealed a seven-bladed Beta-Propeller fold creating seven putative fucose-binding sites per monomer. The crystal structure of the recombinant PLL.L-fucose complex confirmed that at least three sites were fucose-binding. Moreover, the crystal structures indicated that some of the other sites are masked either by the tetrameric nature of the lectin or by incorporation of the C terminus of the lectin into one of these sites. PLL exhibited an ability to bind to insect hemocytes and the cuticular surface of a nematode, H. bacteriophora.

  • The fucose-binding lectin from Ralstonia solanacearum. A new type of Beta-Propeller architecture formed by oligomerization and interacting with fucoside, fucosyllactose, and plant xyloglucan.
    Journal of Biological Chemistry, 2005
    Co-Authors: Nikola Kostlanova, Martina Lahmann, Stefan Oscarson, Nechama Gilboa-garber, Hugues Lortat-jacob, Edward P Mitchell, Michaela Wimmerova, Gérard Chambat, Anne Imberty
    Abstract:

    Plant pathogens, like animal ones, use protein-carbohydrate interactions in their strategy for host recognition, attachment, and invasion. The bacterium Ralstonia solanacearum, which is distributed worldwide and causes lethal wilt in many agricultural crops, was shown to produce a potent L-fucose-binding lectin, R. solanacearum lectin, a small protein of 90 amino acids with a tandem repeat in its amino acid sequence. In the present study, surface plasmon resonance experiments conducted on a series of oligosaccharides show a preference for binding to alphaFuc1-2Gal and alphaFuc1-6Gal epitopes. Titration microcalorimetry demonstrates the presence of two binding sites per monomer and an unusually high affinity of the lectin for alphaFuc1-2Gal-containing oligosaccharides (KD = 2.5 x 10(-7) M for 2-fucosyllactose). R. solanacearum lectin has been crystallized with a methyl derivative of fucose and with the highest affinity ligand, 2-fucosyllactose. X-ray crystal structures, the one with alpha-methyl-fucoside being at ultrahigh resolution, reveal that each monomer consists of two small four-stranded anti-parallel beta-sheets. Trimerization through a 3-fold or pseudo-3-fold axis generates a six-bladed Beta-Propeller architecture, very similar to that previously described for the fungal lectin of Aleuria aurantia. This is the first report of a Beta-Propeller formed by oligomerization and not by sequential domains. Each monomer presents two fucose binding sites, resulting in six symmetrically arranged sugar binding sites for the Beta-Propeller. Crystals were also obtained for a mutated lectin complexed with a fragment of xyloglucan, a fucosylated polysaccharide from the primary cell wall of plants, which may be the biological target of the lectin.

  • crystal structure of fungal lectin six bladed β propeller fold and novel fucose recognition mode for aleuria aurantia lectin
    Journal of Biological Chemistry, 2003
    Co-Authors: Michaela Wimmerova, Jeanfrederic Sanchez, Catherine Gautier, Edward P Mitchell, Anne Imberty
    Abstract:

    Aleuria aurantia lectin is a fungal protein composed of two identical 312-amino acid subunits that specifically recognizes fucosylated glycans. The crystal structure of the lectin complexed with fucose reveals that each monomer consists of a six-bladed Beta-Propeller fold and of a small antiparallel two-stranded beta-sheet that plays a role in dimerization. Five fucose residues were located in binding pockets between the adjacent propeller blades. Due to repeats in the amino acid sequence, there are strong similarities between the sites. Oxygen atoms O-3, O-4, and O-5 of fucose are involved in hydrogen bonds with side chains of amino acids conserved in all repeats, whereas O-1 and O-2 interact with a large number of water molecules. The nonpolar face of each fucose residue is stacked against the aromatic ring of a Trp or Tyr amino acid, and the methyl group is located in a highly hydrophobic pocket. Depending on the precise binding site geometry, the alpha- or beta-anomer of the fucose ligand is observed bound in the crystal. Surface plasmon resonance experiments conducted on a series of oligosaccharides confirm the broad specificity of the lectin, with a slight preference for alphaFuc1-2Gal disaccharide. This multivalent carbohydrate recognition fold is a new prototype of lectins that is proposed to be involved in the host recognition strategy of several pathogenic organisms including not only the fungi Aspergillus but also the phytopathogenic bacterium Ralstonia solanacearum.

  • six bladed s propeller fold and novel fucose recognition modefor aleuria aurantia lectin
    Journal of Biological Chemistry, 2003
    Co-Authors: Michaela Wimmerova, Jeanfrederick Sanchez, Catherine Gautier, Edward P Mitchell, Anne Imberty
    Abstract:

    Aleuria aurantia lectin is a fungal protein composed of two identical 312-amino acid subunits that specifically recognizes fucosylated glycans. The crystal structure of the lectin complexed with fucose reveals that each monomer consists of a six-bladed Beta-Propeller fold and of a small antiparallel two-stranded beta-sheet that plays a role in dimerization. Five fucose residues were located in binding pockets between the adjacent propeller blades. Due to repeats in the amino acid sequence, there are strong similarities between the sites. Oxygen atoms O-3, O-4, and O-5 of fucose are involved in hydrogen bonds with side chains of amino acids conserved in all repeats, whereas O-1 and O-2 interact with a large number of water molecules. The nonpolar face of each fucose residue is stacked against the aromatic ring of a Trp or Tyr amino acid, and the methyl group is located in a highly hydrophobic pocket. Depending on the precise binding site geometry, the alpha-or beta-anomer of the fucose ligand is observed bound in the crystal. Surface plasmon resonance experiments conducted on a series of oligosaccharides confirm the broad specificity of the lectin, with a slight preference for alpha-Fuc1-2Gal disaccharide. This multivalent carbohydrate recognition fold is a new prototype of lectins that is proposed to be involved in the host recognition strategy of several pathogenic organisms including not only the fungi Aspergillus but also the phytopathogenic bacterium Ralstonia solanacearum.

Timothy A Springer - One of the best experts on this subject based on the ideXlab platform.

  • high affinity ligand binding by integrins does not involve head separation
    Journal of Biological Chemistry, 2003
    Co-Authors: Bing Hao Luo, Timothy A Springer, Junichi Takagi
    Abstract:

    Conformational change in the integrin extracellular domain is required for high affinity ligand binding and is also involved in post-ligand binding cellular signaling. Although there is evidence to the contrary, electron microscopic studies showing that ligand binding triggers alpha- and beta-subunit dissociation in the integrin headpiece have gained popularity and support the hypothesis that head separation activates integrins. To test directly the head separation hypothesis, we enforced head association by introducing disulfide bonds across the interface between the alpha-subunit Beta-Propeller domain and the beta-subunit I-like domain. Basal and activation-dependent ligand binding by alpha(IIb)beta(3) and alpha(V)beta(3) was unaffected. The covalent linkage prevented dissociation of alpha(IIb)beta(3) into its subunits on EDTA-treated cells. Whereas EDTA dissociated wild type alpha(IIb)beta(3) on the cell surface, a ligand-mimetic Arg-Gly-Asp peptide did not, as judged by binding of complex-specific antibodies. Finally, a high affinity ligand-mimetic compound stabilized noncovalent association between alpha(IIb) and beta(3) headpiece fragments in the presence of SDS, indicating that ligand binding actually stabilized subunit association at the head, as opposed to the suggested subunit separation. The mechanisms of conformational regulation of integrin function should therefore be considered in the context of the associated alphabeta headpiece.

  • implications for familial hypercholesterolemia from the structure of the ldl receptor ywtd egf domain pair
    Nature Structural & Molecular Biology, 2001
    Co-Authors: Hyesung Jeon, Timothy A Springer, Wuyi Meng, Junichi Takagi, Michael J Eck, Stephen C Blacklow
    Abstract:

    The low-density lipoprotein receptor (LDLR) is the primary mechanism for uptake of cholesterol-carrying particles into cells. The region of the LDLR implicated in receptor recycling and lipoprotein release at low pH contains a pair of calcium-binding EGF-like modules, followed by a series of six YWTD repeats and a third EGF-like module. The crystal structure at 1.5 A resolution of a receptor fragment spanning the YWTD repeats and its two flanking EGF modules reveals that the YWTD repeats form a six-bladed Beta-Propeller that packs tightly against the C-terminal EGF module, whereas the EGF module that precedes the propeller is disordered in the crystal. Numerous point mutations of the LDLR that result in the genetic disease familial hypercholesterolemia (FH) alter side chains that form conserved packing and hydrogen bonding interactions in the interior and between propeller blades. A second subset of FH mutations are located at the interface between the propeller and the C-terminal EGF module, suggesting a structural requirement for maintaining the integrity of the interdomain interface.

  • folding and function of i domain deleted mac 1 and lymphocyte function associated antigen 1
    Journal of Biological Chemistry, 2000
    Co-Authors: Padmaja Yalamanchili, Claus Oxvig, Timothy A Springer
    Abstract:

    In those integrins that contain it, the I domain is a major ligand recognition site. The I domain is inserted between beta-sheets 2 and 3 of the predicted Beta-Propeller domain of the integrin alpha subunit. We deleted the I domain from the integrin alpha(M) and alpha(L) subunits to give I-less Mac-1 and lymphocyte function-associated antigen-1 (LFA-1), respectively. The I-less alpha(M) and alpha(L) subunits were expressed in association with the wild-type beta(2) subunit on the surface of transfected cells and bound to all the monoclonal antibodies mapped to the putative Beta-Propeller and C-terminal regions of the alpha(M) and alpha(L) subunits, suggesting that the folding of these domains is independent of the I domain. I-less Mac-1 bound to the ligands iC3b and factor X, but this binding was reduced compared with wild-type Mac-1. In contrast, I-less Mac-1 did not bind to fibrinogen or denatured bovine serum albumin. Binding to iC3b and factor X by I-less Mac-1 was inhibited by the function-blocking antibody CBRM1/32, which binds to the Beta-Propeller domain of the alpha(M) subunit. I-less LFA-1 did not bind its ligands intercellular adhesion molecule-1 and -3. Thus, the I domain is not essential for the folding, heterodimer formation, and surface expression of Mac-1 and LFA-1 and is required for binding to some ligands, but not others.

  • an extracellular beta propeller module predicted in lipoprotein and scavenger receptors tyrosine kinases epidermal growth factor precursor and extracellular matrix components
    Journal of Molecular Biology, 1998
    Co-Authors: Timothy A Springer
    Abstract:

    An abundant, widely dispersed, extracellular sequence repeat that contains a consensus YWTD motif is shown here to occur in groups of six contiguous repeats. Thirteen lines of evidence, including experimental and computational data, predict with p<3x10(-9) that the repeats do not form tandem domains, but rather each group of six repeats folds into a compact Beta-Propeller structure. The six beta-sheets are arranged about a 6-fold pseudosymmetry axis, and each repeat contributes loops to the faces surrounding the pseudosymmetry axis. Seven different endocytic receptors that contain from one to eight YWTD Beta-Propeller domains act as lipoprotein, vitellogenin, and scavenger receptors. In the low density lipoprotein receptor (LDLR), the many mutations in familial hypercholesterolaemia that map to the YWTD domain can now be interpreted. In the extracellular matrix component nidogen, the YWTD domain functions to bind laminin. Three YWTD domains and interspersed fibronectin type III (FN3) domains constitute almost the entire extracellular domain of the sevenless and c-ros receptor tyrosine kinases. YWTD domains often are bounded by epidermal growth factor (EGF) modules, including in the EGF precursor itself. YWTD Beta-Propellers have a circular folding pattern that brings neighboring modules into close proximity, and may have important consequences for the architecture of multi-domain proteins.

  • folding of the n terminal ligand binding region of integrin α subunits into a β propeller domain
    Proceedings of the National Academy of Sciences of the United States of America, 1997
    Co-Authors: Timothy A Springer
    Abstract:

    The N-terminal approximately 440 aa of integrin alpha subunits contain seven sequence repeats. These are predicted here to fold into a Beta-Propeller domain. A homologous domain from the enzyme phosphatidylinositol phospholipase D is predicted to have the same fold. The domains contain seven four-stranded beta-sheets arranged in a torus around a pseudosymmetry axis. The trimeric G-protein beta subunit (G beta) appears to be the most closely related Beta-Propeller. Integrin ligands and a putative Mg2+ ion are predicted to bind to the upper face of the Beta-Propeller. This face binds substrates in Beta-Propeller enzymes and is used by the G protein beta subunit to bind the G protein alpha subunit. The integrin alpha subunit I domain, which is structurally homologous to the G protein alpha subunit, is tethered to the top of the Beta-Propeller domain by a hinge that may allow movement of the domains relative to one another. The Ca2+-binding motifs in integrin alpha subunits are on the lower face of the Beta-Propeller.

Richard D Emes - One of the best experts on this subject based on the ideXlab platform.

  • a new sequence motif linking lissencephaly treacher collins and oral facial digital type 1 syndromes microtubule dynamics and cell migration
    Human Molecular Genetics, 2001
    Co-Authors: Richard D Emes, Chris P Ponting
    Abstract:

    : A previously unidentified sequence motif has been identified in the products of genes mutated in Miller-Dieker lissencephaly, Treacher Collins, oral-facial-digital type 1 and contiguous syndrome ocular albinism with late onset sensorineural deafness syndromes. An additional homologous motif was detected in a gene product fused to the fibroblast growth factor receptor type 1 in patients with an atypical stem cell myeloproliferative disorder. In total, over 100 eukaryotic intracellular proteins are shown to possess a LIS1 homology (LisH) motif, including several katanin p60 subunits, muskelin, tonneau, LEUNIG, Nopp140, aimless and numerous WD repeat-containing Beta-Propeller proteins. It is suggested that LisH motifs contribute to the regulation of microtubule dynamics, either by mediating dimerization, or else by binding cytoplasmic dynein heavy chain or microtubules directly. The predicted secondary structure of LisH motifs, and their occurrence in homologues of Gbeta Beta-Propeller subunits, suggests that they are analogues of Ggamma subunits, and might associate with the periphery of Beta-Propeller domains. The finding of LisH motifs in both treacle and Nopp140 reinforces previous observations of functional similarities between these nucleolar proteins. Uncharacterized LisH motif-containing proteins represent candidates for other diseases associated with aberrant microtubule dynamics and defects of cell migration, nucleokinesis or chromosome segregation.

  • a new sequence motif linking lissencephaly treacher collins and oral facial digital type 1 syndromes microtubule dynamics and cell migration
    Human Molecular Genetics, 2001
    Co-Authors: Richard D Emes, Chris P Ponting
    Abstract:

    A previously unidentified sequence motif has been identified in the products of genes mutated in Miller-Dieker lissencephaly, Treacher Collins, oral-facial-digital type 1 and contiguous syndrome ocular albinism with late onset sensorineural deafness syndromes. An additional homologous motif was detected in a gene product fused to the fibroblast growth factor receptor type 1 in patients with an atypical stem cell myeloproliferative disorder. In total, over 100 eukaryotic intracellular proteins are shown to possess a LIS1 homology (LisH) motif, including several katanin p60 subunits, muskelin, tonneau, LEUNIG, Nopp140, aimless and numerous WD repeat-containing Beta-Propeller proteins. It is suggested that LisH motifs contribute to the regulation of microtubule dynamics, either by mediating dimerization, or else by binding cytoplasmic dynein heavy chain or microtubules directly. The predicted secondary structure of LisH motifs, and their occurrence in homologues of Gbeta Beta-Propeller subunits, suggests that they are analogues of Ggamma subunits, and might associate with the periphery of Beta-Propeller domains. The finding of LisH motifs in both treacle and Nopp140 reinforces previous observations of functional similarities between these nucleolar proteins. Uncharacterized LisH motif-containing proteins represent candidates for other diseases associated with aberrant microtubule dynamics and defects of cell migration, nucleokinesis or chromosome segregation.