Structural Insights into the Iodothyronine Deiodinase 2 Catalytic Core and Deiodinase Catalysis and Dimerization.

Iodothyronine deiodinases (Dio) are selenocysteine-containing membrane enzymes that activate and inactivate the thyroid hormones (TH) through reductive iodide eliminations. The three deiodinase isoforms are homodimers sharing highly conserved amino acid sequences, but they differ in their regioselectivities for the deiodination reaction and regulatory features. We have now solved a crystal structure of the mouse deiodinase 2 (Dio2) catalytic domain.

Molecular Mechanism of Sirtuin 1 Inhibition by Human Immunodeficiency Virus 1 Tat Protein.

Sirtuins are NAD-dependent protein lysine deacylases implicated in metabolic regulation and aging-related dysfunctions. The nuclear isoform Sirt1 deacetylates histones and transcription factors and contributes, e.g.

Molecular Mechanism of Sirtuin 1 Modulation by the AROS Protein.

The protein lysine deacylases of the NAD-dependent Sirtuin family contribute to metabolic regulation, stress responses, and aging processes, and the human Sirtuin isoforms, Sirt1-7, are considered drug targets for aging-related diseases. The nuclear isoform Sirt1 deacetylates histones and transcription factors to regulate, e.g.

Systemic amyloidoses and proteomics: The state of the art.

Systemic amyloidoses are caused by misfolding-prone proteins that polymerize in tissues, causing organ dysfunction. Since proteins are etiological agents of these diseases, proteomics was soon recognized as a privileged instrument for their investigation. Mass spectrometry-based proteomics has acquired a fundamental role in management of systemic amyloidoses, being now considered a gold standard approach for amyloid typing.

Novel mitochondrial protein interactors of immunoglobulin light chains causing heart amyloidosis.

In immunoglobulin (Ig) light-chain (LC) (AL) amyloidosis, AL deposition translates into life-threatening cardiomyopathy. Clinical and experimental evidence indicates that soluble cardiotoxic LCs are themselves harmful for cells, by which they are internalized. Hypothesizing that interaction of soluble cardiotoxic LCs with cellular proteins contributes to damage, we characterized their interactome in cardiac cells.

Investigating heart-specific toxicity of amyloidogenic immunoglobulin light chains: A lesson from C. elegans.

Abnormalities in protein folding are involved in many localized and systemic diseases, all of which are characterized by insoluble amyloid formation and deposition. In immunoglobulin light chain (LC) amyloidosis, the most frequent systemic form of amyloidosis, the amyloid involvement of the heart dictates the prognosis and the elucidation of the mechanism of heart targeting and toxicity is essential for designing and testing new effective treatments. To this end, the availability of an appropriate animal model is crucial.

Biochemical markers in early diagnosis and management of systemic amyloidoses.

Systemic amyloid diseases are characterized by widespread protein deposition as amyloid fibrils. Precise diagnostic framing is the prerequisite for a correct management of patients. This complex process is achieved through a series of steps, which include detection of the tissue amyloid deposits, identification of the amyloid type, demonstration of the amyloidogenic precursor, and evaluation of organ dysfunction/damage.

A Caenorhabditis elegans-based assay recognizes immunoglobulin light chains causing heart amyloidosis.

Poor prognosis and limited therapeutic options characterize immunoglobulin light-chain (AL) amyloidosis with major heart involvement. Reliable experimental models are needed to study light-chain (LC)/heart interactions and to explore strategies for prevention of cardiac damage. We have exploited the nematode Caenorhabditis elegans as a novel tool, because its pharynx is evolutionarily related to the vertebrate heart.

Crystal structure of human CDC7 kinase in complex with its activator DBF4.

CDC7 is a serine/threonine kinase that is essential for the initiation of eukaryotic DNA replication. CDC7 activity is controlled by its activator, DBF4. Here we present crystal structures of human CDC7-DBF4 in complex with a nucleotide or ATP-competing small molecules, revealing the active and inhibited forms of the kinase, respectively.

Structural analysis of the RZZ complex reveals common ancestry with multisubunit vesicle tethering machinery.

The RZZ complex recruits dynein to kinetochores. We investigated structure, topology, and interactions of the RZZ subunits (ROD, ZWILCH, and ZW10) in vitro, in vivo, and in silico. We identify neuroblastoma-amplified gene (NAG), a ZW10 binder, as a ROD homolog.

Differential expression of AQP1 in microdomain-enriched membranes of renal cell carcinoma.

Human aquaporin-1 (AQP1) is the most studied member of the aquaporin family, acting as molecular water channel. It is also considered a differentiation marker for proximal renal tubular cells, from which clear cells renal cell carcinoma (RCC) originates, playing an important role in urine formation. We therefore studied AQP1 expression at the proteomic level in RCC and normal tissues, mainly focusing on microdomain-enriched membranes in which AQP1 is highly concentrated.

Primary cell cultures arising from normal kidney and renal cell carcinoma retain the proteomic profile of corresponding tissues.

Renal cell carcinoma (RCC) tissue is composed of a mixture of neoplastic and normal cells, which complicate proteome analysis. The aim of our study was to investigate whether it is feasible to establish primary cell cultures of RCC and of renal cortex maintaining the tissue phenotype along with a more homogeneous and enriched cytological material. Fourteen (82.

Expanding the proteome two-dimensional gel electrophoresis reference map of human renal cortex by peptide mass fingerprinting.

Proteomics methodologies hold great promise in basic renal research and clinical nephrology. The classical approach for proteomic analysis couples two-dimensional gel electrophoresis (2-DE) with protein identification by mass spectrometry, to produce more global information regarding normal protein expression and alterations in different physiological and pathological states. In this report we have expanded the identification of proteins in the renal cortex, improving the previously published map to facilitate the study of different diseases affecting the human kidney.

Mutations of the CK2 phosphorylation site of Sic1 affect cell size and S-Cdk kinase activity in Saccharomyces cerevisiae.

By sequence analysis we found an amino acid stretch centred on Serine201 matching a stringent CK2 consensus site within the C-terminal, inhibitory domain of Sic1. Here we show by direct mass spectrometry analysis that Sic1, but not a mutant protein whose CK2 phospho-acceptor site has been mutated to alanine, Sic1S201A, is actually phosphorylated in vitro by CK2 on Serine 201. Mutation of Serine 201 alters the coordination between growth and cell cycle progression.