Calgizarrin like gene (Cal) deficient mice undergo normal spermatogenesis

S100A11: diverse function and pathology corresponding to different target proteins

S100A11, as a member of S100 protein family, while featuring the common identities as the other EF-hand Ca(2+)-binding family members, has its own individual characteristics. S100A11 is widely expressed in multiple tissues, and is located in cytoplasm, nucleus, and even cell periphery. S100A11 exists as a non-covalent homodimer with an antiparallel conformation. Ca(2+) binding to S100A11 would trigger conformational changes which would expose the hydrophobic cleft of S100A11 and facilitate its interaction with target proteins. Since S100A11 appears to lack enzymatic activity, in this article, corresponding to a variety of its target proteins, we systematically describe the biological roles of S100A11 and its possible mechanism in the processes of inflammation, regulation of enzyme activity, and cell growth regulation. As a dual cell growth mediator, S100A11 acts as either a tumor suppressor or promoter in many different types of tumors and would play respective roles in influencing the proliferation of the cancer cells. We intend to illustrate the biological function of the S100 protein, and shed light on the further research, which will provide us with a better understanding of it.

Comparative proteomics profile of osteoblasts cultured on dissimilar hydroxyapatite biomaterials: an iTRAQ-coupled 2-D LC-MS/MS analysis

Hydroxyapatite (HA) and its derived bioceramic materials have been widely used for skeletal implants and/or bone repair scaffolds. It has been reported that carbon nanotube (CNT) is able to enhance the brittle ceramic matrix without detrimental to the bioactivity. However, interaction between osteoblasts and these bioceramics, as well as the underlying mechanism of osteoblast proliferation on these bioceramic surfaces remain to be determined. Using iTRAQ-coupled 2-D LC-MS/MS analysis, we report the first comparative proteomics profiling of human osteoblast cells cultured on plane HA and CNT reinforced HA, respectively. Cytoskeletal proteins, metabolic enzymes, signaling, and cell growth proteins previous associated with cell adhesion and proliferation were found to be differentially expressed on these two surfaces. The level of these proteins was generally higher in cells adhered to HA surface, indicating a higher level of cellular proliferation in these cells. The significance of these findings was further assessed by Western blot analysis. The differential protein profile in HA and CNT strengthened HA established in our study should be valuable for future design of biocompatible ceramics.

Binding of S100 proteins to RAGE: an update

The Receptor for Advanced Glycation Endproducts (RAGE) is a multi-ligand receptor of the immunoglobulin family. RAGE interacts with structurally different ligands probably through the oligomerization of the receptor on the cell surface. However, the exact mechanism is unknown. Among RAGE ligands are members of the S100 protein family. S100 proteins are small calcium binding proteins with high structural homology. Several members of the family have been shown to interact with RAGE in vitro or in cell-based assays. Interestingly, many RAGE ligands appear to interact with distinct domains of the extracellular portion of RAGE and to trigger various cellular effects. In this review, we summarize the modes of S100 protein-RAGE interaction with regard to their cellular functions.

Prm3, the fourth gene in the mouse protamine gene cluster, encodes a conserved acidic protein that affects sperm motility

The protamine gene cluster containing the Prm1, Prm2, Prm3, and Tnp2 genes is present in humans, mice, and rats. The Prm1, Prm2, and Tnp2 genes have been extensively studied, but almost nothing is known about the function and regulation of the Prm3 gene. Here we demonstrate that an intronless Prm3 gene encoding a distinctive small acidic protein is present in 13 species from seven orders of mammals. We also demonstrate that the Prm3 gene has not generated retroposons, which supports the contention that genes that are expressed in meiotic and haploid spermatogenic cells do not generate retroposons. The Prm3 mRNA is first detected in early round spermatids, while the PRM3 protein is first detected in late spermatids. Thus, translation of the Prm3 mRNA is developmentally delayed similar to the Prm1, Prm2, and Tnp2 mRNAs. In contrast to PRM1, PRM2, and TNP2, PRM3 is an acidic protein that is localized in the cytoplasm of elongated spermatids and transfected NIH-3T3 cells. To elucidate the function of PRM3, the Prm3 gene was disrupted by homologous recombination. Sperm from Prm3(-/-) males exhibited reductions in motility, but the fertility of Prm3(-/-) and Prm3(+/+) males was similar in matings of one male and one female. We have developed a competition test in which a mutant male has to compete with a rival wild-type male to fertilize a female; the implications of these results are also discussed.

Investigation of Multiwall Carbon Nanotube Modified Hydroxyapatite on Human Osteoblast Cell Line Using iTRAQ Proteomics Technology

Hydroxyapatite (HA) is a bioactive ceramic material with a chemical composition similar to natural bone, and carbon nano tubes (CNT) is able to enhance the brittle ceramic matrix without detrimental to the bioactivity. This study reported an attempt to use a commercially multiwalled CNT strengthen brittle hydroxyapatite bioceramics. Using iTRAQ-coupled 2D LCMS/ MS analysis, we report the first study of protein profile in osteoblasts from human osteoblastic cell line incubated separately on HA with and without strengthening multiwall CNT surfaces. Sixty proteins were identified and quantified simultaneously at the initial culturing stage of 3 days. The results were validated by Western blotting for selected proteins: Fetuin-A, Elongation factor II and Peroxiredoxin VI. Fetuin-A showed up-regulation, and Peroxiredoxin VI gave down-regulation in the osteoblasts cultured on HA based ceramic surfaces. Similar regulation was expressed by the protein of Elongation factor II on the phase pure HA surfaces as compared to the control group cultured on the polystyrene substrate. Relatively high EF 2 expression was detected on the phase the surfaces of CNT strengthen HA samples.

Pathologies involving the S100 proteins and RAGE

The S100 proteins are exclusively expressed in vertebrates and are the largest subgroup within the superfamily of EF-hand Ca2(+)-binding proteins Generally, S100 proteins are organized as tight homodimers (some as heterodimers). Each subunit is composed of a C-terminal, 'canonical' EF-hand, common to all EF-hand proteins, and a N-terminal, 'pseudo' EF-hand, characteristic of S100 proteins. Upon Ca2(+)-binding, the C-terminal EF-hand undergoes a large conformational change resulting in the exposure of a hydrophobic surface responsible for target binding A unique feature of this protein family is that some members are secreted from cells upon stimulation, exerting cytokine- and chemokine-like extracellular activities via the Receptor for Advanced Glycation Endproducts, RAGE. Recently, larger assemblies of some S100 proteins (hexamers, tetramers, octamers) have been also observed and are suggested to be the active extracellular species required for receptor binding and activation through receptor multimerization Most S100 genes are located in a gene cluster on human chromosome 1q21, a region frequently rearranged in human cancer The functional diversification of S100 proteins is achieved by their specific cell- and tissue-expression patterns, structural variations, different metal ion binding properties (Ca2+, Zn2+ and Cu2+) as well as their ability to form homo-, hetero- and oligomeric assemblies Here, we review the most recent developments focussing on the biological functions of the S100 proteins and we discuss the presently available S100-specific mouse models and their possible use as human disease models In addition, the S100-RAGE interaction and the activation of various cellular pathways will be discussed. Finally, the close association of S100 proteins with cardiomyopathy, cancer, inflammation and brain diseases is summarized as well as their use in diagnosis and their potential as drug targets to improve therapies in the future.

Nuclear expression of S100B in oligodendrocyte progenitor cells correlates with differentiation toward the oligodendroglial lineage and modulates oligodendrocytes maturation

The S100B protein belongs to the S100 family of EF-hand calcium binding proteins implicated in cell growth and differentiation. Here, we show that in the developing and the adult mouse brain, S100B is expressed in oligodendroglial progenitor cells (OPC) committed to differentiate into the oligodendrocyte (OL) lineage. Nuclear S100B accumulation in OPC correlates with the transition from the fast dividing multipotent stage to the morphological differentiated, slow proliferating, pro-OL differentiation stage. In the adult, S100B expression is down-regulated in mature OLs that have established contacts with their axonal targets, suggesting a nuclear S100B function during oligodendroglial cells maturation. In vitro, the morphological transformation and maturation of pro-OL cells are delayed in the absence of S100B. Moreover, mice lacking S100B show an apparent delay in OPC maturation in response to demyelinating insult. We propose that nuclear S100B participates in the regulation of oligodendroglial cell maturation.

S100 proteins in mouse and man: from evolution to function and pathology (including an update of the nomenclature)

The S100 protein family is the largest subgroup within the superfamily of proteins carrying the Ca2+-binding EF-hand motif. Despite their small molecular size and their conserved functional domain of two distinct EF-hands, S100 proteins developed a plethora of tissue-specific intra- and extracellular functions. Accordingly, various diseases such as cardiomyopathies, neurodegenerative and inflammatory disorders, and cancer are associated with altered S100 protein levels. Here, we review the different S100 protein functions and related diseases from an evolutionary point of view. We analyzed the structural variations, which are the basis of functional diversification, as well as the genomic organization of the S100 family in human and compared it with the S100 repertoires in mouse and rat. S100 genes and proteins are highly conserved between the different mammalian species. Moreover, we identified evolutionary related subgroups of S100 proteins within the three species, which share functional similarity and form subclusters on the genomic level. The available S100-specific mouse models are summarized and the consequences of our results are discussed with regard to the use of genetically engineered mice as human disease models. An update of the S100 nomenclature is included, because some of the recently identified S100 genes and pseudogenes had to be renamed.