Protein Health Research Articles

Cardiac titin, the giant sarcomeric protein in health and disease

Ostatnie wyniki badań nad strukturą i funkcją wielkiego białka sarkomerów, titiny (konektyny), otworzyły nowe perspektywy diagnostyki i terapii chorób serca, jak również badań nad ich genetycznym podłożem. Titina pełni zdumiewająco wiele funkcji w sercu (1) kontroluje układ białek kurczliwych w sarkomerze (2) generuje siłę odrzutu przywracającą rozkurczową długość kardiomiocytu podczas jego rozkurczu, a podczas jego rozciągania powyżej spoczynkowej długości generuje bierne napięcie w ścianach serca. Te właściwości titiny są bardzo ważne dla mechaniki lewej komory serca w rozkurczu i dla jej rozkurczowego wypełniania. Ich zaburzenia odgrywają ważną rolę w patofizjologii niewydolności serca. (3) reagując na siły generowane przez sarkomer titina reguluje ekspresję białek kurczliwych w odpowiedzi na zmieniające się obciążenie mięśnia sercowego. W wyniku tego titina jest odpowiedzialna za przerost miocytów w odpowiedzi na ich przeciążenie (4) mutacje titiny zmieniające jej właściwości odgrywają ważną rolę w rozwoju wrodzonych chorób serca takich jak kardiomiopatia rozstrzeniowa i arytmogenna dysplazja prawej komory serca. W niniejszej pracy przedstawiamy podstawowe wyniki badań struktury i funkcji titiny oraz ich wykorzystane dla rozwiązywania niektórych problemów klinicznych.

The pannexins: past and present

The pannexins (Panxs) are a family of chordate proteins homologous to the invertebrate gap junction forming proteins named innexins. Three distinct Panx paralogs (Panx1, Panx2, and Panx3) are shared among the major vertebrate phyla, but they appear to have suppressed (or even lost) their ability to directly couple adjacent cells. Connecting the intracellular and extracellular compartments is now widely accepted as Panx's primary function, facilitating the passive movement of ions and small molecules along electrochemical gradients. The tissue distribution of the Panxs ranges from pervasive to very restricted, depending on the paralog, and are often cell type-specific and/or developmentally regulated within any given tissue. In recent years, Panxs have been implicated in an assortment of physiological and pathophysiological processes, particularly with respect to ATP signaling and inflammation, and they are now considered to be a major player in extracellular purinergic communication. The following is a comprehensive review of the Panx literature, exploring the historical events leading up to their discovery, outlining our current understanding of their biochemistry, and describing the importance of these proteins in health and disease.

In focus in Prague: intermediate filaments

‘‘Intermediate Filaments in Health and Disease’’ were the focus of the scientific program of the 55th Symposium of the Society for Histochemistry in Prague, Czech Republic. Various aspects of intermediate filaments (IF) and associated proteins were presented and discussed with emphasis on imaging and sample preparation methods including both light and electron microscopy and specific labeling techniques. The Symposium was organized in cooperation with BMBS COST Action Nanomechanics of Intermediate Filaments Networks (NANONET) and took place in the Conference Center of the Institute of the Molecular Genetics, Academy of Science of the Czech Republic. Pavel Hozak as the local organizer together with his dedicated team did put together a very exciting and representative program. Robert D. Goldman (Northwestern University Medical School, Chicago, USA) presented the ‘‘Robert Feulgen Lecture’’ sponsored by the Society of Histochemistry and communicated ‘‘Recent Insights into Cytoskeletal and Nucleoskeletal Intermediate Filaments Networks.’’ Ueli Aebi (M.E. Muller Institute for Structural Biology, University of Basel, Switzerland) presented the ‘‘EMBO Lecture’’ and gave a critical appraisal of ‘‘IF Research—Quo Vadis?’’ Nam-On Ku (Yonsei University, Seoul, South Korea) contributed the ‘‘Histochemistry and Cell Biology Lecture 2013’’ and reviewed ‘‘Keratin Function in Simple Type Epithelia’’ (Yi and Ku 2013). In the Session on ‘‘Regulation of IF Assembly and Dynamics in Vivo and in Vitro,’’ Harish C. Pant (Laboratory of Neuronal Cytoskeletal Protein Regulation Section, NINDS, NIH Bethesda, USA) presented an update on the topographic regulation of neuronal IF proteins in health and disease (Binukumar et al. 2013). In the Session on ‘‘IF Structure, Mechanical Properties and Mechanotransduction,’’ Ohad Medalia (Ben-Gurion University, Beer-Sheva, Israel) reviewed structural aspects of lamins and of the nuclear lamina organization as they classically relate to the shape of the nuclear envelope and the nucleus as well as the more recently recognized involvement of lamins in various nuclear functions such as DNA replication and repair, regulation of gene expression, and signaling. A comprehensive and critical appraisal of laminopathies caused by mutations of lamin A, and associated proteins were also presented (Zwerger and Medalia 2013). In the Session on ‘‘IF Associated Proteins and Regulatory Crosstalk in a Cell,’’ Gerhard Wiche (Max F. Perutz Laboratories, University of Vienna, Austria) presented a most comprehensive perspective on plectin-intermediate filament partnership in skin, skeletal muscle, and peripheral nerve. He gave an overview of the structural features and functional properties of plectin and discussed most recent progress in defining the role of its isoforms in stress-prone tissues and the implicated diseases (Castanon et al. 2013). In the same session, Yassemi Capetanaki (Biomedical J. Roth (&) Department of Integrated OMICS for Biomedical Science, WCU Program of Graduate School, Yonsei University, Seoul 120-749, Korea e-mail: jurgen.roth@yonsei.ac.kr

One hundred and fifty years of the Journal of Internal Medicine (JIM)

From this first issue of 2013, the Journal of Internal Medicine will start celebrating its 150th anniversary. The origin of the Journal dates back to 1863 when Medicinskt Archiv was established by Professor Axel Key and his colleagues at the Karolinska Institutet in Stockholm, Sweden. The journal was later renamed Nordiskt Medicinskt Archiv, and in 1919 the name was changed again to Acta Medica Scandinavica (from volume 52). In order to appeal to an international audience it was decided once again to change the name in 1989, to the current Journal of Internal Medicine (JIM) (from volume 225). This latter change was accomplished by the Editor-in-Chief at the time, the late Professor Lars-Erik Böttiger, but not without considerable objection from several Swedish professors of internal medicine 1. During the chairmanships of Professors Lars-Erik Böttiger (1989–1995), Göran Holm (1996–2005) and currently Ulf de Faire (2006–), the Journal has developed into a highly reputed international journal promoting clinical science within a broad range of areas of internal medicine. In 2011, the Journal of Internal Medicine (JIM) was ranked no. 12 of 152 journals listed by the Institute of Science Index (ISI) as Medicine – General and Internal, and the impact factor was 5.483. The number of downloads of articles from the Journal has increasingly risen over recent years with more than 400 000 in 2011. The number of submitted manuscripts has also increased to the current level of about 750 per year with an acceptance rate of about 15%. The journal also publishes reviews, usually commissioned, from leading scientists of important topics within clinical medicine. In addition, the Journal supports international symposia from which review articles are published. Collaboration was established about 10 years ago between the Journal and the Royal Swedish Academy of Sciences, of which Professor Key was also a member, to organize the Key Symposia. These highly ranked symposia, named in honour of the founder of the Journal, are arranged on a yearly basis and particularly focus on translational research. The first symposium in this series was arranged in 2003 and entitled Mild Cognitive Impairment. The two most cited articles published in the Journal as of 19 November 2012 (according to ISI) were reviews from this symposium: Petersen 2 with 1179 citations and Winblad et al. 3 with 922 citations. Since then, the Key Symposia have covered many topics: Long QT Syndromes from Molecule to Man (chaired by Lennart Bergfeldt), Membrane Transport Proteins in Health and Disease (chaired by Anita Aperia), Biology of Ageing (chaired by Nils-Göran Larsson), Mucosal Immunity and Novel HIV-vaccine Concepts (chaired by Jan Andersson and Kristina Broliden), Nanomedicine (chaired by Bengt Fadeel), Molecular Basis of Applied Biologicals and Therapeutics (chaired by Ulf Andersson) and Translational and Systems Biology (chaired by Jens B Nielsen). Articles from these symposia have attracted considerable interest among clinical researchers, resulting in many citations and downloads. The 9th Key Symposium was held recently in December 2012: Updating Alzheimer’s disease diagnosis - implications for prevention and treatment (chaired by Miia Kivipelto). The 10th Key Symposium will be in September 2013 with the preliminary title ‘Taming the Cancer Cell’ (to be chaired by Bengt Westermark). Throughout 2013, the 150th anniversary of the Journal will be indicated by a special logo on the cover of all issues, and also on our Wiley homepage (Fig. 1). In a special anniversary issue published in July, a series of articles will describe the historical developments of a number of topics within internal medicine over the last 150 years. The first article published in Medicinskt Archiv in 1863 by Oskar TH Sandahl 4, which dealt with the physiological and therapeutical effects of compressed air, will be highlighted by a special review of the development of oxygen and hyperbaric oxygen treatment during the past 150 years. Other review articles will show how the Journal has covered scientific breakthroughs over the years within important areas of research such as cardiology. It should also be noted that all published articles in the Journal since 1863 have been digitized and are now available on the Journal website (http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2796/issues). No conflict of interest was declared.

Rab11 proteins in health and disease

Comprising over 60 members, Rab proteins constitute the largest branch of the Ras superfamily of low-molecular-mass G-proteins. This protein family have been primarily implicated in various aspects of intracellular membrane trafficking processes. On the basis of distinct subfamily-specific sequence motifs, many Rabs have been grouped into subfamilies. The Rab11 GTPase subfamily comprises three members: Rab11a, Rab11b and Rab25/Rab11c, which, between them, have been demonstrated to bind more than 30 proteins. In the present paper, we review the function of the Rab11 subfamily. We describe their localization and primary functional roles within the cell and their implication, to date, in disease processes. We also summarize the protein machinery currently known to regulate or mediate their functions and the cargo molecules which they have been shown to transport.

Salivary proteins in health and disease.

Besides their structural catalytic and diverse regulatory functions, proteins are also precursors of many important biological compounds essential for normal functioning of humans. Many of these compounds may be used as markers for identification of specific pathological states. A comprehensive knowledge about the metabolism of salivary proteins and the mechanisms of action of their metabolites allowed the development of effective treatment for many disorders. However, it should not be forgotten that in some pathological conditions, these compounds not only could be involved in the pathogenesis but also could be used as tool in the prediction of many diseases. This paper is a review of the published literature on selected salivary proteins in the context of the physiological processes of the human body and chosen chronic disorders, such as diabetes, diabetic nephropathy, mucositis, oral mycoses and caries.

A phenotype survey of 36 mutant mouse strains with gene-targeted defects in glycosyltransferases or glycan-binding proteins

The consortium for functional glycomics (CFG) was a large research initiative providing networking and resources for investigators studying the role of glycans and glycan-binding proteins in health and disease. Starting in 2001, six scientific cores were established to generate data, materials and new technologies. By the end of funding in 2011, the mouse phenotype core (MPC) submitted data to a website from the phenotype screen of 36 mutant mouse strains deficient in a gene for either a glycan-binding protein (GBP) or glycosyltransferase (GT). Each mutant strain was allotted three months for analysis and screened by standard phenotype assays used in the fields of immunology, histology, hematology, coagulation, serum chemistry, metabolism and behavior. Twenty of the deficient mouse strains had been studied in other laboratories, and additional tests were performed on these strains to confirm previous observations and discover new data. The CFG constructed 16 new homozygous mutant mouse strains and completed the initial phenotype screen of the majority of these new mutant strains. In total, >300 phenotype changes were observed, but considering the over 100 assays performed on each strain, most of the phenotypes were unchanged. Phenotype differences include abnormal testis morphology in GlcNAcT9- and Siglec-H-deficient mice and lethality in Pomgnt1-deficient mice. The numerous altered phenotypes discovered, along with the consideration of the significant findings of normality, will provide a platform for future characterization to understand the important roles of glycans and GBPs in the mechanisms of health and disease.

LIV-1 ZIP Ectodomain Shedding in Prion-Infected Mice Resembles Cellular Response to Transition Metal Starvation

We recently documented the co-purification of members of the LIV-1 subfamily of ZIP (Zrt-, Irt-like Protein) zinc transporters (LZTs) with the cellular prion protein (PrP(C)) and, subsequently, established that the prion gene family descended from an ancestral LZT gene. Here, we begin to address whether the study of LZTs can shed light on the biology of prion proteins in health and disease. Starting from an observation of an abnormal LZT immunoreactive band in prion-infected mice, subsequent cell biological analyses uncovered a surprisingly coordinated biology of ZIP10 (an LZT member) and prion proteins that involves alterations to N-glycosylation and endoproteolysis in response to manipulations to the extracellular divalent cation milieu. Starving cells of manganese or zinc, but not copper, causes shedding of the N1 fragment of PrP(C) and of the ectodomain of ZIP10. For ZIP10, this posttranslational biology is influenced by an interaction between its PrP-like ectodomain and a conserved metal coordination site within its C-terminal multi-spanning transmembrane domain. The transition metal starvation-induced cleavage of ZIP10 can be differentiated by an immature N-glycosylation signature from a constitutive cleavage targeting the same site. Data from this work provide a first glimpse into a hitherto neglected molecular biology that ties PrP to its LZT cousins and suggest that manganese or zinc starvation may contribute to the etiology of prion disease in mice.

Is losartan the drug for all seasons?

Francesco Ramirez is the Dr. Amy and James Elster Professor of Molecular Biology (Connective Tissue Diseases) in the Department of Pharmacology and Systems Therapeutics at the Mount Sinai School of Medicine in New York City. His long-standing research interest focuses on the role of ECM proteins in health and disease. Major accomplishments include the characterization of genetic lesions and pathophysiological mechanisms in osteogenesis imperfecta, Ehlers-Danlos syndrome, spondyloepiphyseal dysplasia, congenital contractural arachnodactyly and Marfan syndrome.

Isoprenoids and Related Pharmacological Interventions: Potential Application in Alzheimer’s Disease

Two major isoprenoids, farnesyl pyrophosphate and geranylgeranyl pyrophosphate, serve as lipid donors for the posttranslational modification (known as prenylation) of proteins that possess a characteristic C-terminal motif. The prenylation reaction is catalyzed by prenyltransferases. The lipid prenyl group facilitates to anchor the proteins in cell membranes and mediates protein-protein interactions. A variety of important intracellular proteins undergo prenylation, including almost all members of small GTPase superfamilies as well as heterotrimeric G protein subunits and nuclear lamins. These prenylated proteins are involved in regulating a wide range of cellular processes and functions, such as cell growth, differentiation, cytoskeletal organization, and vesicle trafficking. Prenylated proteins are also implicated in the pathogenesis of different types of diseases. Consequently, isoprenoids and/or prenyltransferases have emerged as attractive therapeutic targets for combating various disorders. This review attempts to summarize the pharmacological agents currently available or under development that control isoprenoid availability and/or the process of prenylation, mainly focusing on statins, bisphosphonates, and prenyltransferase inhibitors. Whereas statins and bisphosphonates deplete the production of isoprenoids by inhibiting the activity of upstream enzymes, prenyltransferase inhibitors directly block the prenylation of proteins. As the importance of isoprenoids and prenylated proteins in health and disease continues to emerge, the therapeutic potential of these pharmacological agents has expanded across multiple disciplines. This review mainly discusses their potential application in Alzheimer's disease.

Dynamic distribution of claudin proteins in pancreatic epithelia undergoing morphogenesis or neoplastic transformation.

The assembly of distinct proteins into tight junctions results in the formation of a continuous barrier that regulates the paracellular flux of water, ions, and small molecules across epithelia. The claudin protein family encompasses numerous major structural components of tight junctions. These proteins specify the permeability characteristics of tight junctions and consequently, some of the physiological properties of epithelia. Furthermore, defective claudin expression has been found to correlate with some diseases, tumor progression, and defective morphogenesis. Investigating the pattern of claudin expression during embryogenesis or in certain pathological conditions is necessary to begin disclosing the role of these proteins in health and disease. This study analyzed the expression of several claudins during mouse pancreas organogenesis and in pancreatic intraepithelial neoplasias of mouse and human origin. Our results underscored a distinctive, dynamic distribution of certain claudins in both the developing pancreas and the pancreatic epithelium undergoing neoplastic transformation.

Ubiquitin-mediated regulation of RhoGTPase signalling: IAPs and HACE1 enter the fray

Ubiquitin-mediated regulation of RhoGTPase signalling: IAPs and HACE1 enter the fray

Kidins220/ARMS as a functional mediator of multiple receptor signalling pathways

An increasing body of evidence suggests that several membrane receptors--in addition to activating distinct signalling cascades--also engage in substantial crosstalk with each other, thereby adjusting their signalling outcome as a function of specific input information. However, little is known about the molecular mechanisms that control their coordination and integration of downstream signalling. A protein that is likely to have a role in this process is kinase-D-interacting substrate of 220 kDa [Kidins220, also known as ankyrin repeat-rich membrane spanning (ARMS), hereafter referred to as Kidins220/ARMS]. Kidins220/ARMS is a conserved membrane protein that is preferentially expressed in the nervous system and interacts with the microtubule and actin cytoskeleton. It interacts with neurotrophin, ephrin, vascular endothelial growth factor (VEGF) and glutamate receptors, and is a common downstream target of several trophic stimuli. Kidins220/ARMS is required for neuronal differentiation and survival, and its expression levels modulate synaptic plasticity. Kidins220/ARMS knockout mice show developmental defects mainly in the nervous and cardiovascular systems, suggesting a crucial role for this protein in modulating the cross talk between different signalling pathways. In this Commentary, we summarise existing knowledge regarding the physiological functions of Kidins220/ARMS, and highlight some interesting directions for future studies on the role of this protein in health and disease.

At the Fulcrum in Health and Disease: Cdk5 and the Balancing Acts of Neuronal Structure and Physiology.

Cdk5 has been implicated in a multitude of processes in neuronal development, cell biology and physiology. These influence many neurological disorders, but the very breadth of Cdk5 effects has made it difficult to synthesize a coherent picture of the part played by this protein in health and disease. In this review, we focus on the roles of Cdk5 in neuronal function, particularly synaptic homeostasis, plasticity, neurotransmission, subcellular organization, and trafficking. We then discuss how disruption of these Cdk5 activities may initiate or exacerbate neural disorders. A recurring theme will be the sensitivity of Cdk5 sequelae to the precise biological context under consideration.

Ultraviolet radiation-induced upregulation of antimicrobial proteins in health and disease

This article reviews recent data on the expression, regulation and activation of antimicrobial peptides (AMP) in human skin, and considers their potential protective and pro-inflammatory roles following upregulation by ultraviolet radiation (UVR). Antimicrobial peptides are small peptides that are key components of the innate immune system, originally identified by their vital role in protecting the body-environment interface from infection. However, it has now become clear that AMP have more extensive actions, including the provision of pivotal links with the adaptive immune system. Moreover, aberrant AMP expression may contribute to immuno-modulated inflammatory dermatoses including psoriasis, eczema and the photoaggravated condition lupus erythematosus. Recent work has demonstrated the direct upregulation of AMP in healthy skin by cutaneous UVR exposure. This may serve to protect the skin from risks imposed by both the biophysical barrier-compromise and the immunosuppression that are attributable to UVR exposure. Furthermore, it is observed that UVR provokes upregulation of AMP in an atypical manner in the photosensitivity disorder polymorphic light eruption. Dysregulated UVR responses of these pro-inflammatory proteins may play a role in the pathogenesis of certain immune-mediated diseases caused or aggravated by sunlight.

The universe of Hsp90.

Abstract Molecular chaperones are key components in the maintenance of cellular homeostasis and survival, not only during stress but also under optimal growth conditions. Among the ATP-dependent chaperones, heat shock proteins (Hsp90) proteins play a special role. While Hsp90s can interact with unfolded and misfolded proteins, their main (and in eukaryotic cells essential) function appears to involve interactions with a limited number of protein clients at late steps of maturation or in "alter-native" conformations for regulating their stability and activity. Because Hsp90 clients are hubs of diverse signaling networks and participate in nearly every cellular function, Hsp90s interconnect many regulatory circuits and link them to environmental impacts. The availability and activity of Hsp90 may thus influence complex physiological and pathophysiological processes, such as differentiation, development, aging, cancer, neurodegeneration, and infectious diseases. Furthermore, through homeostatic effects on differentiation and development, Hsp90s act as capacitors of phenotypic evolution. In this review, we discuss recent insights in the structure and chaperone cycle of Hsp90s, the mechanisms underlying Hsp90 binding to clients, and potential reasons why client proteins specifically require the assistance of Hsp90s. Moreover, the current views on Hsp90-cochaperone interactions and regulation of Hsp90 proteins via posttranslational modifications are summarized. The second half of this article is devoted to the role of Hsp90 proteins in health and disease, aging, and evolution.

Mapping the differential distribution of glycosaminoglycans in the adult human retina, choroid, and sclera.

PURPOSE. To map the distribution of different classes of glycosaminoglycans (GAGs) in the healthy human retina, choroid, and sclera. METHODS. Frozen tissue sections were made from adult human donor eyes. The GAG chains of proteoglycans (PGs) were detected with antibodies directed against various GAG structures (either directly or after pretreatment with GAG-degrading enzymes); hyaluronan (HA) was detected using biotinylated recombinant G1-domain of human versican. The primary detection reagents were identified with FITC-labeled probes and analyzed by fluorescence microscopy. RESULTS. Heparan sulfate (HS), chondroitin sulfate (CS), dermatan sulfate (DS), and HA were present throughout the retina and choroid, but keratan sulfate (KS) was detected only in the sclera. HS labeling was particularly strong in basement membrane-containing structures, the nerve fiber layer (NFL), and retinal pigment epithelium (RPE)-for example, intense staining was seen with an antibody that binds strongly to sequences containing 3-O-sulfation in the internal limiting membrane (ILM) and in the basement membrane of blood vessels. Unsulfated CS was seen throughout the retina, particularly in the ILM and interphotoreceptor matrix (IPM) with 6-O-sulfated CS also prominent in the IPM. There was labeling for DS throughout the retina and choroid, especially in the NFL, ganglion cell layer, and blood vessels. CONCLUSIONS. The detection of GAG chains with specific probes and fluorescence microscopy provides for the first time a detailed analysis of their compartmentalization in the human retina, by both GAG chain type and sulfation pattern. This reference map provides a basis for understanding the functional regulation of GAG-binding proteins in health and disease processes.

New insights on sarcoplasmic reticulum calcium regulation in muscle fatigue

a consistent observation with fatigue in skeletal muscle is a decline in the amplitude of the myoplasmic Ca2+ transient, which is thought to result primarily from a reduced Ca2+ flux through the ryanodine receptor (RyR1) of the sarcoplasmic reticulum (SR) ([Fig. 1][1]). This in turn is thought to

Modification of citrulline residues with 2,3‐butanedione facilitates their detection by liquid chromatography/mass spectrometry

Citrullination is a post-translational modification (PTM) that results from the deimination of the amino acid arginine into citrulline by Peptidyl Arginine Deiminase enzymes and occurs in a wide range of proteins in health and disease. This modification causes a 1 Da mass shift, which can be used to identify citrullination sites in proteins by the use of mass spectrometry. However, other PTMs, such as deamidation from asparagine to aspartic acid or from glutamine to glutamic acid, can also cause a 1 Da mass shift, making correct interpretation of the data more difficult. We developed a chemical tagging strategy which, combined with an open source search application, allowed us to selectively pinpoint citrullinated peptides in a complex mixture after liquid chromatography/mass spectrometry (LC/MS) analysis. After incubation of a peptide mixture with 2,3 butanedione, citrulline residues were covalently modified which resulted in a 50 Da shift in singly charged mass. By comparison of the peptide mass fingerprint from a modified and an unmodified version of the same sample, our in-house search application was able to identify the citrullinated peptides in the mixture. This strategy was optimized on synthetic peptides and validated on a digest of in vitro citrullinated fibrinogen, where different proteolytic enzymes were used to augment the protein coverage. This new method results in easy detection of citrullinated residues, without the need for complex mass spectrometry equipment.

Two-Component Systems and Their Co-Option for Eukaryotic Signal Transduction

Two-component signaling pathways involve histidine kinases, response regulators, and sometimes histidine-containing phosphotransfer proteins. Prevalent in prokaryotes, these signaling elements have also been co-opted to meet the needs of signal transduction in eukaryotes such as fungi and plants. Here we consider the evolution of such regulatory systems, with a particular emphasis on the roles they play in signaling by the plant hormones cytokinin and ethylene, in phytochrome-mediated perception of light, and as integral components of the circadian clock.