Characterization of Centrin Genes in <i>Paramecium</i>

Madeddu, Luisa; Klotz, Catherine; Caër, Jean-Pierre Le; Beisson, Janine

doi:10.1111/j.1432-1033.1996.0121q.x

Cited by 67 publications

(59 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From the N-terminal peptide sequence of the centrin isoform ICL1, we characterised four nearly identical centrin genes: ICL1a, ICL1b, ICL1c and ICL1d (Madeddu et al, 1996). The frequent occurrence of such multigene families encoding nearly identical proteins in the Paramecium genome, finds its origin in the three successive rounds of whole genome duplication that occurred during Paramecium tetraurelia evolution (Aury et al, 2006).…”

Section: Resultsmentioning

confidence: 99%

Functional diversification of centrins and cell morphological complexity

Gogendeau

Klotz

Arnaiz

et al. 2008

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

In addition to their key role in the duplication of microtubule organising centres (MTOCs), centrins are major constituents of diverse MTOC-associated contractile arrays. A centrin partner, Sfi1p, has been characterised in yeast as a large protein carrying multiple centrin-binding sites, suggesting a model for centrin-mediated Ca2+-induced contractility and for the duplication of MTOCs. In vivo validation of this model has been obtained in Paramecium, which possesses an extended contractile array – the infraciliary lattice (ICL) – essentially composed of centrins and a huge Sfi1p-like protein, PtCenBP1p, which is essential for ICL assembly and contractility. The high molecular diversity revealed here by the proteomic analysis of the ICL, including ten subfamilies of centrins and two subfamilies of Sf1p-like proteins, led us to address the question of the functional redundancy, either between the centrin-binding proteins or between the centrin subfamilies. We show that all are essential for ICL biogenesis. The two centrin-binding protein subfamilies and nine of the centrin subfamilies are ICL specific and play a role in its molecular and supramolecular architecture. The tenth and most conserved centrin subfamily is present at three cortical locations (ICL, basal bodies and contractile vacuole pores) and might play a role in coordinating duplication and positioning of cortical organelles.

show abstract

Section: Resultsmentioning

confidence: 99%

Functional diversification of centrins and cell morphological complexity

Gogendeau

Klotz

Arnaiz

et al. 2008

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…Although the gene of this 23-24-kD large contractile protein has been cloned in Paramecium (Madeddu et al 1996;Klotz et al 1997), detailed information on its potential phosphorylation is still required. In the Paramecium cortex, Abs against Ser/Thr phosphorylation sites recognize a variety of proteins of у20 kD (Keryer et al 1987), and cortical morphogenesis depends on the phosphorylation state of some basal body-associated proteins (Sperling et al 1991), as shown, e.g., in Figure 10.…”

Section: Can At the Infraciliary Latticementioning

confidence: 99%

Quantitative Immunogold Localization of Protein Phosphatase 2B (Calcineurin) inParameciumCells

Momayezi

Kissmehl

Plattner

2000

J Histochem Cytochem.

View full text Add to dashboard Cite

S U M M A R YFor immunogold EM labeling analysis, we fixed Paramecium cells in 4% formaldehyde and 0.125% glutaraldehyde, followed by low-temperature embedding in unicryl and UV polymerization. We first quantified some obvious but thus far neglected side effects of section staining on immunogold labeling, using mono-or polyclonal antibodies (Abs) against defined secretory and cell surface components, followed by F(ab) 2 -or protein A-gold conjugates. Use of alkaline lead staining resulted in considerable rearrangement and loss of label unless sections were postfixed by glutaraldehyde after gold labeling. This artifact is specific for section staining with lead. It can be avoided by staining sections with aqueous uranyl acetate only to achieve high-resolution immunogold localization of a protein phosphatase on unicryl sections. In general, phosphatases are assumed to be closely, although loosely, associated with their targets. Because the occurrence of protein phosphatase 2B (calcineurin) in Paramecium has been previously established by biochemical and immunological work, as well as by molecular biology, we have used Abs against mammalian CaN or its subunits, CaN-A and CaN-B, for antigen mapping in these cells by quantitative immunogold labeling analysis. Using ABs against whole CaN, four structures are selectively labeled (with slightly decreasing intensity), i.e., infraciliary lattice (centrin-containing contractile cortical filament network), parasomal sacs (coated pits), and outlines of alveolar sacs (subplasmalemmal calcium stores, tightly attached to the cell membrane), as well as rims of chromatin-containing nuclear domains. In other subcellular regions, gold granules reached densities three to four times above background outside the cell but there was no selective enrichment, e.g., in cilia, ciliary basal bodies, cytosol, mitochondria, trichocysts (dense-core secretory organelles), and non-chromatin nuclear domains. Their labeling density was 4-to 8.5-fold (average 6.5-fold) less than that on selectively labeled structures. Labeling tendency was about the same with Abs against either subunit. Our findings may facilitate the examination of molecular targets contained in the selectively labeled structures.

show abstract

“…The ICL of Paramecium is a Ca 2ϩ -associated contractile cytoskeletal network made of bundles of 4-nm filaments subtending the whole cell surface (1). In previous biochemical and genetic studies, we have identified, in addition to at least 10 centrin isoforms (12,24), a large centrinassociated protein (L-CAP; Ͼ350 kDa) as a major component of the ICL (20). We show here that L-CAP, hereinafter referred to as PtCenBP1p (for P. tetraurelia centrin-binding protein 1), is indeed an Sfi1p-like protein which presents the same remarkable succession of centrin-binding sites over the whole length of the molecule.…”

mentioning

confidence: 99%

An Sfi1p-Like Centrin-Binding Protein Mediates Centrin-Based Ca ²⁺ -Dependent Contractility in Paramecium tetraurelia

et al. 2007

Self Cite

View full text Add to dashboard Cite

Centrins are EF-hand calcium-binding proteins conserved in all eukaryotes, where they localize as a discrete component at microtubule-organizing centers. Their implication in the duplication of the spindle pole body (SPB) in Saccharomyces cerevisiae (6, 41), of the centrosome in mammalian cells (6,26,37), and of basal bodies in ciliates and flagellates is well documented (21, 31, 39, 43, 45). In unicellular organisms, centrins are also associated with different organelles, like cilia (14, 15) and contractile vacuole pores (43), and are major constituents of diverse contractile organelles, such as the striated flagellar roots of Tetraselmis striata, where centrin was first characterized (34); the nucleus-basal body connector and the striated fibers of Chlamydomonas reinhardtii (35); the spasmoneme of Vorticella convallaria (2); and the infraciliary lattice

show abstract

Characterization of Centrin Genes in Paramecium

Cited by 67 publications

References 45 publications

Functional diversification of centrins and cell morphological complexity

Functional diversification of centrins and cell morphological complexity

Quantitative Immunogold Localization of Protein Phosphatase 2B (Calcineurin) inParameciumCells

An Sfi1p-Like Centrin-Binding Protein Mediates Centrin-Based Ca ²⁺ -Dependent Contractility in Paramecium tetraurelia

Contact Info

Product

Resources

About

Characterization of Centrin Genes in Paramecium

Cited by 67 publications

References 45 publications

Functional diversification of centrins and cell morphological complexity

Functional diversification of centrins and cell morphological complexity

Quantitative Immunogold Localization of Protein Phosphatase 2B (Calcineurin) inParameciumCells

An Sfi1p-Like Centrin-Binding Protein Mediates Centrin-Based Ca 2+ -Dependent Contractility in Paramecium tetraurelia

Contact Info

Product

Resources

About

An Sfi1p-Like Centrin-Binding Protein Mediates Centrin-Based Ca ²⁺ -Dependent Contractility in Paramecium tetraurelia