Enzyme activity is regulated by several mechanisms, including phosphorylation. Phosphorylation is a key signal transduction process in all eukaryotic cells and is thus crucial for virtually all cellular processes. In addition to its direct effect on protein structure, phosphorylation also affects protein-protein interactions, such as binding to scaffolding 14-3-3 proteins, which selectively recognize phosphorylated motifs. These interactions then modulate the catalytic activity, cellular localisation and interactions of phosphorylated enzymes through different mechanisms. The aim of this mini-review is to highlight several examples of 14-3-3 protein-dependent mechanisms of enzyme regulation previously studied in our laboratory over the past decade. More specifically, we address here the regulation of the human enzymes ubiquitin ligase Nedd4-2, procaspase-2, calcium-calmodulin dependent kinases CaMKK1/2, and death-associated protein kinase 2 (DAPK2) and yeast neutral trehalase Nth1.

• MeSH
• fosforylace MeSH
• lidé MeSH
• proteiny 14-3-3 * metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• proteiny 14-3-3 * MeSH

Cell signaling regulates several physiological processes by receiving, processing, and transmitting signals between the extracellular and intracellular environments. In signal transduction, phosphorylation is a crucial effector as the most common posttranslational modification. Selectively recognizing specific phosphorylated motifs of target proteins and modulating their functions through binding interactions, the yeast 14-3-3 proteins Bmh1 and Bmh2 are involved in catabolite repression, carbon metabolism, endocytosis, and mitochondrial retrograde signaling, among other key cellular processes. These conserved scaffolding molecules also mediate crosstalk between ubiquitination and phosphorylation, the spatiotemporal control of meiosis, and the activity of ion transporters Trk1 and Nha1. In humans, deregulation of analogous processes triggers the development of serious diseases, such as diabetes, cancer, viral infections, microbial conditions and neuronal and age-related diseases. Accordingly, the aim of this review article is to provide a brief overview of the latest findings on the functions of yeast 14-3-3 proteins, focusing on their role in modulating the aforementioned processes.

• Klíčová slova
• 14-3-3 proteins, adaptor protein, molecular mechanism, phosphorylation, protein-protein interaction, scaffolding, yeast,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Ca2+ /CaM-dependent protein kinase kinases 1 and 2 (CaMKK1 and CaMKK2) phosphorylate and enhance the catalytic activity of downstream kinases CaMKI, CaMKIV, and protein kinase B. Accordingly, CaMKK1 and CaMKK2 regulate key physiological and pathological processes, such as tumorigenesis, neuronal morphogenesis, synaptic plasticity, transcription factor activation, and cellular energy homeostasis, and promote cell survival. Both CaMKKs are partly inhibited by phosphorylation, which in turn triggers adaptor and scaffolding protein 14-3-3 binding. However, 14-3-3 binding only significantly affects CaMKK1 function. CaMKK2 activity remains almost unchanged after complex formation for reasons still unclear. Here, we aim at structurally characterizing CaMKK1:14-3-3 and CaMKK2:14-3-3 complexes by SAXS, H/D exchange coupled to MS, and fluorescence spectroscopy. The results revealed that complex formation suppresses the interaction of both phosphorylated CaMKKs with Ca2+ /CaM and affects the structure of their kinase domains and autoinhibitory segments. But these effects are much stronger on CaMKK1 than on CaMKK2 because the CaMKK1:14-3-3γ complex has a more compact and rigid structure in which the active site of the kinase domain directly interacts with the last two C-terminal helices of the 14-3-3γ protein, thereby inhibiting CaMKK1. In contrast, the CaMKK2:14-3-3 complex has a looser and more flexible structure, so 14-3-3 binding only negligibly affects the catalytic activity of CaMKK2. Therefore, Ca2+ /CaM binding suppression and the interaction of the kinase active site of CaMKK1 with the last two C-terminal helices of 14-3-3γ protein provide the structural basis for 14-3-3-mediated CaMKK1 inhibition.

• Klíčová slova
• 14-3-3 proteins, CaMKK, SAXS, calcium/calmodulin-dependent protein kinase, fluorescence spectroscopy, hydrogen/deuterium exchange coupled to MS, protein-protein interaction,
• MeSH
• difrakce rentgenového záření MeSH
• fosforylace MeSH
• katalytická doména MeSH
• kinasa proteinkinasy závislé na vápníku a kalmodulinu * chemie   metabolismus   MeSH
• maloúhlový rozptyl MeSH
• proteiny 14-3-3 * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kinasa proteinkinasy závislé na vápníku a kalmodulinu * MeSH
• proteiny 14-3-3 * MeSH

Therapeutic strategies targeting nuclear receptors (NRs) beyond their endogenous ligand binding pocket have gained significant scientific interest driven by a need to circumvent problems associated with drug resistance and pharmacological profile. The hub protein 14-3-3 is an endogenous regulator of various NRs, providing a novel entry point for small molecule modulation of NR activity. Exemplified, 14-3-3 binding to the C-terminal F-domain of the estrogen receptor alpha (ERα), and small molecule stabilization of the ERα/14-3-3ζ protein complex by the natural product Fusicoccin A (FC-A), was demonstrated to downregulate ERα-mediated breast cancer proliferation. This presents a novel drug discovery approach to target ERα; however, structural and mechanistic insights into ERα/14-3-3 complex formation are lacking. Here, we provide an in-depth molecular understanding of the ERα/14-3-3ζ complex by isolating 14-3-3ζ in complex with an ERα protein construct comprising its ligand-binding domain (LBD) and phosphorylated F-domain. Bacterial co-expression and co-purification of the ERα/14-3-3ζ complex, followed by extensive biophysical and structural characterization, revealed a tetrameric complex between the ERα homodimer and the 14-3-3ζ homodimer. 14-3-3ζ binding to ERα, and ERα/14-3-3ζ complex stabilization by FC-A, appeared to be orthogonal to ERα endogenous agonist (E2) binding, E2-induced conformational changes, and cofactor recruitment. Similarly, the ERα antagonist 4-hydroxytamoxifen inhibited cofactor recruitment to the ERα LBD while ERα was bound to 14-3-3ζ. Furthermore, stabilization of the ERα/14-3-3ζ protein complex by FC-A was not influenced by the disease-associated and 4-hydroxytamoxifen resistant ERα-Y537S mutant. Together, these molecular and mechanistic insights provide direction for targeting ERα via the ERα/14-3-3 complex as an alternative drug discovery approach.

• Klíčová slova
• 14-3-3 protein, Estrogen Receptor, Nuclear receptors, PPI stabilization, protein–protein interactions,
• MeSH
• alfa receptor estrogenů * genetika   metabolismus   MeSH
• antagonisté estrogenu farmakologie   MeSH
• lidé MeSH
• ligandy MeSH
• objevování léků MeSH
• proteiny 14-3-3 * genetika   metabolismus   MeSH
• tamoxifen farmakologie   MeSH
• vazba proteinů účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• afimoxifene MeSH Prohlížeč
• alfa receptor estrogenů * MeSH
• antagonisté estrogenu MeSH
• ligandy MeSH
• proteiny 14-3-3 * MeSH
• tamoxifen MeSH

Signal transduction cascades efficiently transmit chemical and/or physical signals from the extracellular environment to intracellular compartments, thereby eliciting an appropriate cellular response. Most often, these signaling processes are mediated by specific protein-protein interactions involving hundreds of different receptors, enzymes, transcription factors, and signaling, adaptor and scaffolding proteins. Among them, 14-3-3 proteins are a family of highly conserved scaffolding molecules expressed in all eukaryotes, where they modulate the function of other proteins, primarily in a phosphorylation-dependent manner. Through these binding interactions, 14-3-3 proteins participate in key cellular processes, such as cell-cycle control, apoptosis, signal transduction, energy metabolism, and protein trafficking. To date, several hundreds of 14-3-3 binding partners have been identified, including protein kinases, phosphatases, receptors and transcription factors, which have been implicated in the onset of various diseases. As such, 14-3-3 proteins are promising targets for pharmaceutical interventions. However, despite intensive research into their protein-protein interactions, our understanding of the molecular mechanisms whereby 14-3-3 proteins regulate the functions of their binding partners remains insufficient. This review article provides an overview of the current state of the art of the molecular mechanisms whereby 14-3-3 proteins regulate their binding partners, focusing on recent structural studies of 14-3-3 protein complexes.

• Klíčová slova
• 14-3-3 proteins, adaptor protein, molecular mechanism, phosphorylation, protein-protein interactions, scaffolding,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

14-3-3 proteins are important dimeric scaffolds that regulate the function of hundreds of proteins in a phosphorylation-dependent manner. The SARS-CoV-2 nucleocapsid (N) protein forms a complex with human 14-3-3 proteins upon phosphorylation, which has also been described for other coronaviruses. Here, we report a high-resolution crystal structure of 14-3-3 bound to an N phosphopeptide bearing the phosphoserine 197 in the middle. The structure revealed two copies of the N phosphopeptide bound, each in the central binding groove of each 14-3-3 monomer. A complex network of hydrogen bonds and water bridges between the peptide and 14-3-3 was observed explaining the high affinity of the N protein for 14-3-3 proteins.

• MeSH
• COVID-19 MeSH
• fosfopeptidy chemie   MeSH
• fosfoproteiny chemie   MeSH
• koronavirové nukleokapsidové proteiny * chemie   MeSH
• lidé MeSH
• proteiny 14-3-3 * chemie   MeSH
• SARS-CoV-2 * MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfopeptidy MeSH
• fosfoproteiny MeSH
• koronavirové nukleokapsidové proteiny * MeSH
• nucleocapsid phosphoprotein, SARS-CoV-2 MeSH Prohlížeč
• proteiny 14-3-3 * MeSH

Expansion of the polyglutamine tract in the N terminus of Ataxin-1 is the main cause of the neurodegenerative disease, spinocerebellar ataxia type 1 (SCA1). However, the C-terminal part of the protein - including its AXH domain and a phosphorylation on residue serine 776 - also plays a crucial role in disease development. This phosphorylation event is known to be crucial for the interaction of Ataxin-1 with the 14-3-3 adaptor proteins and has been shown to indirectly contribute to Ataxin-1 stability. Here we show that 14-3-3 also has a direct anti-aggregation or "chaperone" effect on Ataxin-1. Furthermore, we provide structural and biophysical information revealing how phosphorylated S776 in the intrinsically disordered C terminus of Ataxin-1 mediates the cytoplasmic interaction with 14-3-3 proteins. Based on these findings, we propose that 14-3-3 exerts the observed chaperone effect by interfering with Ataxin-1 dimerization through its AXH domain, reducing further self-association. The chaperone effect is particularly important in the context of SCA1, as it was previously shown that a soluble form of mutant Ataxin-1 is the major driver of pathology.

• Klíčová slova
• HDX-MS, SAXS, crystal structure, neurodegeneration, protein aggregation,
• MeSH
• ataxin-1 chemie   metabolismus   MeSH
• buněčné linie MeSH
• cytoplazma metabolismus   MeSH
• fosforylace MeSH
• HEK293 buňky MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• multimerizace proteinu MeSH
• proteinové domény MeSH
• proteiny 14-3-3 metabolismus   MeSH
• stabilita proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ataxin-1 MeSH
• ATXN1 protein, human MeSH Prohlížeč
• proteiny 14-3-3 MeSH

Death-associated protein kinase 2 (DAPK2) is a CaM-regulated Ser/Thr protein kinase, involved in apoptosis, autophagy, granulocyte differentiation and motility regulation, whose activity is controlled by autoinhibition, autophosphorylation, dimerization and interaction with scaffolding proteins 14-3-3. However, the structural basis of 14-3-3-mediated DAPK2 regulation remains unclear. Here, we structurally and biochemically characterize the full-length human DAPK2:14-3-3 complex by combining several biophysical techniques. The results from our X-ray crystallographic analysis revealed that Thr369 phosphorylation at the DAPK2 C terminus creates a high-affinity canonical mode III 14-3-3-binding motif, further enhanced by the diterpene glycoside Fusicoccin A. Moreover, concentration-dependent DAPK2 dimerization is disrupted by Ca2+/CaM binding and stabilized by 14-3-3 binding in solution, thereby protecting the DAPK2 inhibitory autophosphorylation site Ser318 against dephosphorylation and preventing Ca2+/CaM binding. Overall, our findings provide mechanistic insights into 14-3-3-mediated DAPK2 inhibition and highlight the potential of the DAPK2:14-3-3 complex as a target for anti-inflammatory therapies.

• MeSH
• dimerizace MeSH
• fosforylace MeSH
• lidé MeSH
• proteinkinasy asociované se smrtí genetika   metabolismus   MeSH
• proteiny 14-3-3 genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DAPK2 protein, human MeSH Prohlížeč
• proteinkinasy asociované se smrtí MeSH
• proteiny 14-3-3 MeSH
• YWHAG protein, human MeSH Prohlížeč

Neural precursor cell expressed developmentally down-regulated 4 ligase (Nedd4-2) is an E3 ubiquitin ligase that targets proteins for ubiquitination and endocytosis, thereby regulating numerous ion channels, membrane receptors and tumor suppressors. Nedd4-2 activity is regulated by autoinhibition, calcium binding, oxidative stress, substrate binding, phosphorylation and 14-3-3 protein binding. However, the structural basis of 14-3-3-mediated Nedd4-2 regulation remains poorly understood. Here, we combined several techniques of integrative structural biology to characterize Nedd4-2 and its complex with 14-3-3. We demonstrate that phosphorylated Ser342 and Ser448 are the key residues that facilitate 14-3-3 protein binding to Nedd4-2 and that 14-3-3 protein binding induces a structural rearrangement of Nedd4-2 by inhibiting interactions between its structured domains. Overall, our findings provide the structural glimpse into the 14-3-3-mediated Nedd4-2 regulation and highlight the potential of the Nedd4-2:14-3-3 complex as a pharmacological target for Nedd4-2-associated diseases such as hypertension, epilepsy, kidney disease and cancer.

• MeSH
• down regulace MeSH
• fosforylace MeSH
• myši genetika   metabolismus   MeSH
• proteiny 14-3-3 genetika   metabolismus   MeSH
• ubikvitinace MeSH
• ubikvitinligasy Nedd4 genetika   metabolismus   MeSH
• vazba proteinů MeSH
• WW domény * MeSH
• zvířata MeSH
• Check Tag
• myši genetika   metabolismus   MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• Nedd4l protein, mouse MeSH Prohlížeč
• proteiny 14-3-3 MeSH
• Sfn protein, mouse MeSH Prohlížeč
• ubikvitinligasy Nedd4 MeSH

Phosphorylation by kinases governs many key cellular and extracellular processes, such as transcription, cell cycle progression, differentiation, secretion and apoptosis. Unsurprisingly, tight and precise kinase regulation is a prerequisite for normal cell functioning, whereas kinase dysregulation often leads to disease. Moreover, the functions of many kinases are regulated through protein-protein interactions, which in turn are mediated by phosphorylated motifs and often involve associations with the scaffolding and chaperon protein 14-3-3. Therefore, the aim of this review article is to provide an overview of the state of the art on 14-3-3-mediated kinase regulation, focusing on the most recent mechanistic insights into these important protein-protein interactions and discussing in detail both their structural aspects and functional consequences.

• Klíčová slova
• 14-3-3, ASK1, CaMKK2, LRRK2, PI4KB, PKC, RAF kinase, kinase, phosphorylation,
• MeSH
• alosterická regulace genetika   MeSH
• apoptóza genetika   MeSH
• fosforylace genetika   MeSH
• lidé MeSH
• mitogenem aktivované proteinkinasy p38 genetika   MeSH
• proteinkinasy genetika   MeSH
• proteiny 14-3-3 genetika   MeSH
• signální transdukce genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• mitogenem aktivované proteinkinasy p38 MeSH
• proteinkinasy MeSH
• proteiny 14-3-3 MeSH