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Flagellar Proteins (flagellar + protein)

Distribution by Scientific Domains

Life Sciences	80%

Selected Abstracts

Microtubule sliding movement in tilapia sperm flagella axoneme is regulated by Ca2+/calmodulin-dependent protein phosphorylation

CYTOSKELETON, Issue 8 2006
Masaya Morita
Abstract Demembranated euryhaline tilapia Oreochromis mossambicus sperm were reactivated in the presence of concentrations in excess of 10,6 M Ca2+. Motility features changed when Ca2+ concentrations were increased from 10,6 to 10,5 M. Although the beat frequency did not increase, the shear angle and wave amplitude of flagellar beating increased, suggesting that the sliding velocity of microtubules in the axoneme, which represents dynein activity, rises with an increase in Ca2+. Thus, it is possible that Ca2+ binds to flagellar proteins to activate flagellar motility as a result of the enhanced dynein activity. One Ca2+ -binding protein (18 kDa, pI 4.0), calmodulin (CaM), was detected by 45Ca overlay assay and immunologically. A CaM antagonist, W-7, suppressed the reactivation ratio and swimming speed, suggesting that the 18 kDa Ca2+ -binding protein is CaM and that CaM regulates flagellar motility. CaMKIV was detected immunologically as a single 48 kDa band in both the fraction of low ion extract of the axoneme and the remnant of the axoneme, suggesting that CaMKIV binds to distinct positions in the axoneme. It is possible that CaMKIV phosphorylates the axonemal proteins in a Ca2+/CaM-dependent manner for regulating the dynein activity. A 32P-uptake in the axoneme showed that 48, 75, 120, 200, 250, 380, and 400 kDa proteins were phosphorylated in a Ca2+/CaM kinase-dependent manner. Proteins (380 kDa) were phosphorylated in the presence of 10,5 M Ca2+. It is possible that an increase in Ca2+ induces Ca2+/CaM kinase-dependent regulation, including protein phosphorylation for activation/regulation of dynein activity in flagellar axoneme. Cell Motil. Cytoskeleton 2006. © 2006 Wiley-Liss, Inc. [source]

Control of flatfish sperm motility by CO2 and carbonic anhydrase

CYTOSKELETON, Issue 3 2003
Kazuo Inaba
Abstract Sperm motility in flatfishes shows unique characteristics. The flagellar movement either in vivo or in permeabilized models is arrested by the presence of 25,100 mM HCO3,, or by gentle perfusion with CO2 gas. To understand the molecular basis of this property, sperm Triton-soluble proteins and flagellar proteins from several species were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. An abundant 29-kDa protein was observed only in flatfish species. Partial amino acid sequences identified this protein as a carbonic anhydrase, an enzyme involved in the interconversion of CO2 and HCO3,. 6-ethoxyzolamide, a specific inhibitor of carbonic anhydrase inhibits sperm motility, especially at low pH. In the case of HCO3, -arrested sperm, the motility is restored by addition of 6-ethoxyzolamide. Taken together, these results suggest that a novel pH/ HCO3, -dependent regulatory mechanism mediated by carbonic anhydrase is involved in the motility control in flatfish sperm. Cell Motil. Cytoskeleton 55:174,187, 2003. © 2003 Wiley-Liss, Inc. [source]

Helicobacter pylori HP1034 (ylxH) is required for motility

HELICOBACTER, Issue 5 2004
Karin Van Amsterdam
ABSTRACT Background.,Helicobacter pylori motility is essential for the colonization and persistence in the human gastric mucosa. So far, more than 50 genes have been described to play a role in flagellar biosynthesis. H. pylori YlxH (HP1034) is annotated as an ATP-binding protein. However, H. pylori YlxH shows similarity to proteins involved in the flagellar biosynthesis of other bacterial species. Moreover, H. pylori ylxH is found adjacent to genes involved in flagellar biosynthesis in the sequenced genomes of H. pylori 26695 and J99. We therefore aimed to determine the role of YlxH in H. pylori motility. Materials and methods., Motility, flagellar biosynthesis and transcriptional regulation of genes encoding flagellar proteins was compared between H. pylori 11A and a knockout of ylxH in H. pylori 11A. Results., The ylxH knockout in H. pylori 11A was nonmotile on soft agar plates, whereas H. pylori 11A was motile. Furthermore, the H. pylori 11A ylxH knockout lacked flagella, while H. pylori 11A possessed two to three flagella. Transcription of H. pylori flaG (HP0751), fliM (HP1031) and fliA (HP1032) was reduced in the H. pylori 11A ylxH¯ knockout, whereas transcription of flaA (HP0601) was not altered. However, Western blot analysis showed substantially reduced amounts of the major flagellin subunit FlaA in the H. pylori 11A ylxH knockout compared to H. pylori 11A. Conclusions.,H. pylori YlxH is essential for the assembly of flagella and hence for the motility of H. pylori. [source]

Tyrphostin-A47 inhibitable tyrosine phosphorylation of flagellar proteins is associated with distinct alteration of motility pattern in hamster spermatozoa

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 2 2006
Daniel Mariappa
Abstract To acquire fertilizing potential, mammalian spermatozoa must undergo capacitation and acrosome reaction. Our earlier work showed that pentoxifylline (0.45 mM), a sperm motility stimulant, induced an early onset of hamster sperm capacitation associated with tyrosine phosphorylation of 45,80 kDa proteins, localized to the mid-piece of the sperm tail. To assess the role of protein tyrosine phosphorylation in sperm capacitation, we used tyrphostin-A47 (TP-47), a specific protein tyrosine kinase inhibitor. The dose-dependent (0.1,0.5 mM) inhibition of tyrosine phosphorylation by TP-47 was associated with inhibition of hyperactivated motility and 0.5 mM TP-47-treated spermatozoa exhibited a distinct circular motility pattern. This was accompanied by hypo-tyrosine phosphorylation of 45,60 kDa proteins, localized to the principal piece of the intact-sperm and the outer dense fiber-like structures in detergent treated-sperm. Sperm kinematic analysis (by CASA) of spermatozoa, exhibiting circular motility (at 1st hr), showed lower values of straight line velocity, curvilinear velocity and average path velocity, compared to untreated controls. Other TP-47 analogues, tyrphostin-AG1478 and -AG1296, had no effect either on kinematic parameters or sperm protein tyrosine phosphorylation. These studies indicate that TP-47-induced circular motility of spermatozoa is compound-specific and that the tyrosine phosphorylation status of 45,60 kDa flagellum-localized proteins could be key regulators of sperm flagellar bending pattern, associated with the hyperactivation of hamster spermatozoa. Mol. Reprod. Dev. © 2005 Wiley-Liss, Inc. [source]

Application of immunoproteomics to leptospirosis: towards clinical diagnostics and vaccine discovery

PROTEOMICS - CLINICAL APPLICATIONS, Issue 4 2007
Uraiwan Kositanont
Abstract Each of the currently available methods for serodiagnosis of leptospirosis, including the microscopic agglutination test (MAT), has its own drawback(s) when used in clinical practice. A new diagnostic test is therefore required for an earlier and more accurate diagnosis of leptospirosis. We applied immunoproteomics to define potential immunogens from five serovars of Leptospira reference strains. A leptospiral whole cell lysate from each serovar was used as the antigen to react with IgG and IgM in the sera from four patients with a positive MAT. Sera from four non-leptospirosis patients with a negative MAT were pooled and used as the negative control. 2-D Western blot analysis showed that the degree of immunoreactivity corresponded with the MAT titers. No immunoreactive spots were detected when the pooled control sera were used. A total of 24 protein spots immunoreacted with IgM and/or IgG from patients with leptospirosis. These immunoreactive proteins were identified by MALDI-TOF MS and were classified into five groups, including flagellar proteins, chaperones/heat shock proteins, transport proteins, metabolic enzymes, and hypothetical proteins. More immunoreactive spots were detected with anti-human IgG in the sera of all patients and with all the serovars of leptospires used. Some of the identified proteins immunoreacted only with IgG, whereas the others were detectable with both IgM and IgG. Among the immunoreactive proteins identified, FlaB proteins (flagellin and flagellar core protein) have been shown to have a potential role in clinical diagnostics and vaccine development. These data underscore the significant impact of immunoproteomics in clinical applications. [source]