Autocitrullination and Changes in the Activity of Peptidylarginine Deiminase 3 Induced by High Ca Concentrations.

Peptidylarginine deiminases (PADs) are enzymes that catalyze the Ca-dependent conversion of arginine residues into proteins to citrulline residues. Five PAD isozymes have been identified in mammals. Several studies have shown that the active-site pockets of these isozymes are formed when Ca ions are properly bound.

Structures of human peptidylarginine deiminase type III provide insights into substrate recognition and inhibitor design.

Peptidylarginine deiminase type III (PAD3) is an isozyme belonging to the PAD enzyme family that converts arginine to citrulline residue(s) within proteins. PAD3 is expressed in most differentiated keratinocytes of the epidermis and hair follicles, while S100A3, trichohyalin, and filaggrin are its principal substrates. In this study, the X-ray crystal structures of PAD3 in six states, including its complex with the PAD inhibitor Cl-amidine, were determined.

Deimination and Peptidylarginine Deiminases in Skin Physiology and Diseases.

Deimination, also known as citrullination, corresponds to the conversion of the amino acid arginine, within a peptide sequence, into the non-standard amino acid citrulline. This post-translational modification is catalyzed by a family of calcium-dependent enzymes called peptidylarginine deiminases (PADs). Deimination is implicated in a growing number of physiological processes (innate and adaptive immunity, gene regulation, embryonic development, etc.

Peptidylarginine Deiminase Inhibitor Cl-Amidine Attenuates Cornification and Interferes with the Regulation of Autophagy in Reconstructed Human Epidermis.

Deimination, a post-translational modification catalyzed by a family of enzymes called peptidylarginine deiminases (PADs), is the conversion of arginine into citrulline residues in a protein. Deimination has been associated with numerous physiological and pathological processes. Our aim was to study its implication in the homeostasis of human epidermis, where three PADs are expressed, namely PAD1, 2, and 3.

Lowering relative humidity level increases epidermal protein deimination and drives human filaggrin breakdown.

Background: Deimination (also known as citrullination), the conversion of arginine in a protein to citrulline, is catalyzed by a family of enzymes called peptidylarginine deiminases (PADs). Three PADs are expressed in the epidermis, one of their targets being filaggrin. Filaggrin plays a central role in atopic dermatitis and is a key protein for the epidermal barrier.

Deimination of Human Hornerin Enhances its Processing by Calpain-1 and its Cross-Linking by Transglutaminases.

Hornerin (HRNR) shares numerous features with filaggrin, a key contributor to the epidermal barrier functions. The two proteins display a related structural organization, are expressed by the granular keratinocytes as a large precursor processed by proteolysis, and are cross-linked to the cornified cell envelopes. Two main steps in the metabolism of filaggrin are its deimination and calpain-1 cleavage.

Monomeric Form of Peptidylarginine Deiminase Type I Revealed by X-ray Crystallography and Small-Angle X-ray Scattering.

Peptidylarginine deiminase (PAD; EC 3.5.3.

Acefylline activates filaggrin deimination by peptidylarginine deiminases in the upper epidermis.

Background: Peptidylarginine deiminases (PADs) catalyze deimination (or citrullination), a calcium-dependent post-translational modification involved in several physiological processes and human diseases, such as rheumatoid arthritis and cancer. Deimination of filaggrin (FLG) by PAD1 and PAD3 during the last steps of keratinocyte differentiation is a crucial event for the epidermis function and homeostasis. This allows the complete degradation of FLG, leading to the production of free amino acids and their derivatives that are essential for epidermal photoprotection and moisturizing of the stratum corneum.

Crystallization and preliminary X-ray crystallographic analysis of human peptidylarginine deiminase type I.

Peptidylarginine deiminase (PAD) catalyzes the post-translational conversion of peptidylarginine to peptidylcitrulline in the presence of calcium ions. Among the five known human PAD isozymes (PAD1-4 and PAD6), PAD1 exhibits the broadest substrate specificity. Crystals of PAD1 obtained using polyethylene glycol 3350 as a precipitant diffracted to 3.

Three isozymes of peptidylarginine deiminase in the chicken: molecular cloning, characterization, and tissue distribution.

Peptidylarginine deiminase (PAD; EC 3.5.3.

Purification and characterization of the human cysteine-rich S100A3 protein and its pseudo citrullinated forms expressed in insect cells.

High quantity and quality of recombinant Ca(2+)-binding proteins are required to study their molecular interactions, self-assembly, posttranslational modifications, and biological activities to elucidate Ca(2+)-dependent cellular signaling pathways. S100A3 is a unique member of the S100 protein family with the highest cysteine content (10%). This protein, derived from human hair follicles and cuticles, is characterized by an N-terminal acetyl group and irreversible posttranslational citrullination by peptidylarginine deiminase causing its homotetramer assembly.

Human S100A3 tetramerization propagates Ca(2+)/Zn(2+) binding states.

The S100A3 homotetramer assembles upon citrullination of a specific symmetric Arg51 pair on its homodimer interface in human hair cuticular cells. Each S100A3 subunit contains two EF-hand-type Ca(2+)-binding motifs and one (Cys)3His-type Zn(2+)-binding site in the C-terminus. The C-terminal coiled domain is cross-linked to the presumed docking surface of the dimeric S100A3 via a disulfide bridge.

Crystallization and preliminary X-ray crystallographic analysis of human peptidylarginine deiminase type III.

In the presence of calcium ions, human peptidylarginine deiminase (PAD) converts arginine residues in proteins to citrulline. Of the five known human PAD enzymes, the type III isozyme (PAD3) exhibits the highest specificity for synthetic and natural substrates. This study aimed to determine the structure of PAD3 in order to elucidate its selective citrullination mechanism.

S100 and S100 fused-type protein families in epidermal maturation with special focus on S100A3 in mammalian hair cuticles.

Epithelial Ca(2+)-regulation, which governs cornified envelope formation in the skin epidermis and hair follicles, closely coincides with the expression of S100A3, filaggrin and trichohyalin, and the post-translational modification of these proteins by Ca(2+)-dependent peptidylarginine deiminases. This review summarizes the current nomenclature and evolutional aspects of S100 Ca(2+)-binding proteins and S100 fused-type proteins (SFTPs) classified as a separate protein family with special reference to the molecular structure and function of S100A3 dominantly expressed in hair cuticular cells. Both S100 and SFTP family members are identified by two distinct types of Ca(2+)-binding loops in an N-terminal pseudo EF-hand motif followed by a canonical EF-hand motif.

Caspase-14 is required for filaggrin degradation to natural moisturizing factors in the skin.

Caspase-14 is a protease that is mainly expressed in suprabasal epidermal layers and activated during keratinocyte cornification. Caspase-14-deficient mice display reduced epidermal barrier function and increased sensitivity to UVB radiation. In these mice, profilaggrin, a protein with a pivotal role in skin barrier function, is processed correctly to its functional filaggrin (FLG) repeat unit, but proteolytic FLG fragments accumulate in the epidermis.

Deimination of human filaggrin-2 promotes its proteolysis by calpain 1.

Filaggrin-2 (FLG2), a member of the S100-fused type protein family, shares numerous features with filaggrin (FLG), a key protein implicated in the epidermal barrier functions. Both display a related structural organization, an identical pattern of expression and localization in human epidermis, and proteolytic processing of a large precursor. Here, we tested whether FLG2 was a substrate of calpain 1, a calcium-dependent protease directly involved in FLG catabolism.

Refined crystal structures of human Ca(2+)/Zn(2+)-binding S100A3 protein characterized by two disulfide bridges.

S100A3, a member of the EF-hand-type Ca(2+)-binding S100 protein family, is unique in its exceptionally high cysteine content and Zn(2+) affinity. We produced human S100A3 protein and its mutants in insect cells using a baculovirus expression system. The purified wild-type S100A3 and the pseudo-citrullinated form (R51A) were crystallized with ammonium sulfate in N,N-bis(2-hydroxyethyl)glycine buffer and, specifically for postrefolding treatment, with Ca(2+)/Zn(2+) supplementation.

An intronic enhancer driven by NF-κB contributes to transcriptional regulation of peptidylarginine deiminase type I gene in human keratinocytes.

Peptidylarginine deiminases (PADs) catalyze the conversion of protein-bound arginine to citrulline residues. In human epidermis, where filaggrin is the main deiminated protein, three PADs are detected with specific patterns of expression depending on the keratinocyte (KC) differentiation state. Previous characterizations of the PAD-encoding gene promoters have shown that proximal regulation alone is not sufficient to explain this specificity of expression.

Substrate specificity and kinetic studies of PADs 1, 3, and 4 identify potent and selective inhibitors of protein arginine deiminase 3.

Protein citrullination has been shown to regulate numerous physiological pathways (e.g., the innate immune response and gene transcription) and is, when dysregulated, known to be associated with numerous human diseases, including cancer, rheumatoid arthritis, and multiple sclerosis.

Deimination is regulated at multiple levels including auto-deimination of peptidylarginine deiminases.

Peptidylarginine deiminases (PADs) catalyze deimination, converting arginyl to citrullyl residues. Only three PAD isotypes are detected in the epidermis where they play a crucial role, targeting filaggrin, a key actor for the tissue hydration and barrier functions. Their expression and activation depends on the keratinocyte differentiation state.

Neutral cysteine protease bleomycin hydrolase is essential for the breakdown of deiminated filaggrin into amino acids.

Filaggrin is a component of the cornified cell envelope and the precursor of free amino acids acting as a natural moisturizing factor in the stratum corneum. Deimination is critical for the degradation of filaggrin into free amino acids. In this study, we tried to identify the enzyme(s) responsible for the cleavage of deiminated filaggrin in vitro.

Mechanical stretching elevates peptidyl arginine deiminase 2 expression in astrocytes.

Purpose: To determine whether the mechanical stretching renders modulation of the peptidyl arginine deiminase 2 (PAD2) expression in cultured astrocytes.

Methods: Isolated rat brain astrocytes were subjected to mechanical stretching using a glass bead set-up and polyethylene set-up with or without immobilization. Activity assays and ELISA were performed to detect PAD2 expression.

Molecular characterization of a novel soybean gene encoding a neutral PR-5 protein induced by high-salt stress.

In this study, we characterized a novel soybean gene encoding a neutral PR-5 protein and compared it to two acidic isoforms of soybean PR-5 protein. This gene, designated as Glycine max osmotin-like protein, b isoform (GmOLPb, accession no. AB370233), encoded a putative protein having the greatest similarity to chickpea PR-5b (89% identity).

Transcriptional regulation of peptidylarginine deiminase expression in human keratinocytes.

Peptidylarginine deiminase (PAD, EC 3.5.3.

Long-range enhancer differentially regulated by c-Jun and JunD controls peptidylarginine deiminase-3 gene in keratinocytes.

Long-range cis elements are critical regulators of transcription, particularly for clustered paralogous genes. Such are the five PADI genes in 1p35-36 encoding peptidylarginine deiminases, which catalyze deimination, a Ca2+-dependent post-translational modification. Deimination has been implicated in the pathophysiology of severe human diseases such as multiple sclerosis and rheumatoid arthritis.