scholarly journals Accessory proteins of the zDHHC family of S-acylation enzymes

2020 ◽  
Vol 133 (22) ◽  
pp. jcs251819
Author(s):  
Christine Salaun ◽  
Carolina Locatelli ◽  
Filip Zmuda ◽  
Juan Cabrera González ◽  
Luke H. Chamberlain
Keyword(s):  
Fatty Acyl ◽  
Accessory Proteins ◽  
Enzyme Substrate ◽  
Essential Components ◽  
Selenoprotein K ◽  
Acyl Chains ◽  
The Stability ◽  
And Function ◽  
Encoding Genes

ABSTRACTAlmost two decades have passed since seminal work in Saccharomyces cerevisiae identified zinc finger DHHC domain-containing (zDHHC) enzymes as S-acyltransferases. These enzymes are ubiquitous in the eukarya domain, with 23 distinct zDHHC-encoding genes in the human genome. zDHHC enzymes mediate the bulk of S-acylation (also known as palmitoylation) reactions in cells, transferring acyl chains to cysteine thiolates, and in so-doing affecting the stability, localisation and function of several thousand proteins. Studies using purified components have shown that the minimal requirements for S-acylation are an appropriate zDHHC enzyme–substrate pair and fatty acyl-CoA. However, additional proteins including GCP16 (also known as Golga7), Golga7b, huntingtin and selenoprotein K, have been suggested to regulate the activity, stability and trafficking of certain zDHHC enzymes. In this Review, we discuss the role of these accessory proteins as essential components of the cellular S-acylation system.

scholarly journals Prediction of Functional Consequences of Missense Mutations in ANO4 Gene

2021 ◽  
Vol 22 (5) ◽  
pp. 2732
Author(s):  
Nadine Reichhart ◽  
Vladimir M. Milenkovic ◽  
Christian H. Wetzel ◽  
Olaf Strauß
Keyword(s):  
Transmembrane Protein ◽  
Functional Characterization ◽  
Missense Mutations ◽  
Mutant Proteins ◽  
Functional Consequences ◽  
New Perspective ◽  
The Stability ◽  
Dynamics Simulations ◽  
And Function

The anoctamin (TMEM16) family of transmembrane protein consists of ten members in vertebrates, which act as Ca2+-dependent ion channels and/or Ca2+-dependent scramblases. ANO4 which is primarily expressed in the CNS and certain endocrine glands, has been associated with various neuronal disorders. Therefore, we focused our study on prioritizing missense mutations that are assumed to alter the structure and stability of ANO4 protein. We employed a wide array of evolution and structure based in silico prediction methods to identify potentially deleterious missense mutations in the ANO4 gene. Identified pathogenic mutations were then mapped to the modeled human ANO4 structure and the effects of missense mutations were studied on the atomic level using molecular dynamics simulations. Our data show that the G80A and A500T mutations significantly alter the stability of the mutant proteins, thus providing new perspective on the role of missense mutations in ANO4 gene. Results obtained in this study may help to identify disease associated mutations which affect ANO4 protein structure and function and might facilitate future functional characterization of ANO4.

How do mechanosensitive channels sense membrane tension?

2016 ◽  
Vol 44 (4) ◽  
pp. 1019-1025 ◽  
Author(s):  
Tim Rasmussen
Keyword(s):  
Membrane Lipids ◽  
Osmotic Shock ◽  
Md Simulations ◽  
Fatty Acyl ◽  
Membrane Bilayer ◽  
Cross Sectional ◽  
Conducting Path ◽  
Lipid Chain ◽  
Acyl Chains

Mechanosensitive (MS) channels provide protection against hypo-osmotic shock in bacteria whereas eukaryotic MS channels fulfil a multitude of important functions beside osmoregulation. Interactions with the membrane lipids are responsible for the sensing of mechanical force for most known MS channels. It emerged recently that not only prokaryotic, but also eukaryotic, MS channels are able to directly sense the tension in the membrane bilayer without any additional cofactor. If the membrane is solely viewed as a continuous medium with specific anisotropic physical properties, the sensitivity towards tension changes can be explained as result of the hydrophobic coupling between membrane and transmembrane (TM) regions of the channel. The increased cross-sectional area of the MS channel in the active conformation and elastic deformations of the membrane close to the channel have been described as important factors. However, recent studies suggest that molecular interactions of lipids with the channels could play an important role in mechanosensation. Pockets in between TM helices were identified in the MS channel of small conductance (MscS) and YnaI that are filled with lipids. Less lipids are present in the open state of MscS than the closed according to MD simulations. Thus it was suggested that exclusion of lipid fatty acyl chains from these pockets, as a consequence of increased tension, would trigger gating. Similarly, in the eukaryotic MS channel TRAAK it was found that a lipid chain blocks the conducting path in the closed state. The role of these specific lipid interactions in mechanosensation are highlighted in this review.

scholarly journals Viperin catalyzes methionine oxidation to promote protein expression and function of helicases

2019 ◽  
Vol 5 (8) ◽  
pp. eaax1031 ◽  
Author(s):  
Lei Bai ◽  
Jiazhen Dong ◽  
Zhenqiu Liu ◽  
Youliang Rao ◽  
Pinghui Feng ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Methionine Oxidation ◽  
Biological Processes ◽  
Loss Of Function ◽  
Rna Helicases ◽  
Dna And Rna ◽  
Biochemical Studies ◽  
The Stability ◽  
And Function

Helicases play pivotal roles in fundamental biological processes, and posttranslational modifications regulate the localization, function, and stability of helicases. Here, we report that methionine oxidation of representative helicases, including DNA and RNA helicases of viral (ORF44 of KSHV) and cellular (MCM7 and RIG-I) origin, promotes their expression and functions. Cellular viperin, a major antiviral interferon-stimulated gene whose functions beyond host defense remain largely unknown, catalyzes the methionine oxidation of these helicases. Moreover, biochemical studies entailing loss-of-function mutations of helicases and a pharmacological inhibitor interfering with lipid metabolism and, hence, decreasing viperin activity indicate that methionine oxidation potently increases the stability and enzyme activity of these helicases that are critical for DNA replication and immune activation. Our work uncovers a pivotal role of viperin in catalyzing the methionine oxidation of helicases that are implicated in diverse fundamental biological processes.

scholarly journals A nanobody-based molecular toolkit provides new mechanistic insight into clathrin-coat initiation

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Linton M Traub
Keyword(s):  
Decisive Role ◽  
Subcellular Location ◽  
Combined Approach ◽  
Mechanistic Insight ◽  
Early Endosomes ◽  
The Stability ◽  
And Function ◽  
Insight Into ◽  
Complementarity Determining Region

Besides AP-2 and clathrin triskelia, clathrin coat inception depends on a group of early-arriving proteins including Fcho1/2 and Eps15/R. Using genome-edited cells, we described the role of the unstructured Fcho linker in stable AP-2 membrane deposition. Here, expanding this strategy in combination with a new set of llama nanobodies against EPS15 shows an FCHO1/2–EPS15/R partnership plays a decisive role in coat initiation. A nanobody containing an Asn-Pro-Phe peptide within the complementarity-determining region 3 loop is a function-blocking pseudoligand for tandem EPS15/R EH domains. Yet, in living cells, EH domains gathered at clathrin-coated structures are poorly accessible, indicating residence by endogenous NPF-bearing partners. Forcibly sequestering cytosolic EPS15 in genome-edited cells with nanobodies tethered to early endosomes or mitochondria changes the subcellular location and availability of EPS15. This combined approach has strong effects on clathrin coat structure and function by dictating the stability of AP-2 assemblies at the plasma membrane.

scholarly journals Regulatory effects of post-translational modifications on zDHHC S-acyltransferases

2020 ◽  
Vol 295 (43) ◽  
pp. 14640-14652
Author(s):  
Filip Zmuda ◽  
Luke H. Chamberlain
Keyword(s):  
Drug Targets ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Fatty Acyl Chain ◽  
Physiological Importance ◽  
Cellular Processes ◽  
Cell Growth And Differentiation ◽  
Regulatory Effects ◽  
The Stability ◽  
And Function

The human zDHHC S-acyltransferase family comprises 23 enzymes that mediate the S-acylation of a multitude of cellular proteins, including channels, receptors, transporters, signaling molecules, scaffolds, and chaperones. This reversible post-transitional modification (PTM) involves the attachment of a fatty acyl chain, usually derived from palmitoyl-CoA, to specific cysteine residues on target proteins, which affects their stability, localization, and function. These outcomes are essential to control many processes, including synaptic transmission and plasticity, cell growth and differentiation, and infectivity of viruses and other pathogens. Given the physiological importance of S-acylation, it is unsurprising that perturbations in this process, including mutations in ZDHHC genes, have been linked to different neurological pathologies and cancers, and there is growing interest in zDHHC enzymes as novel drug targets. Although zDHHC enzymes control a diverse array of cellular processes and are associated with major disorders, our understanding of these enzymes is surprisingly incomplete, particularly with regard to the regulatory mechanisms controlling these enzymes. However, there is growing evidence highlighting the role of different PTMs in this process. In this review, we discuss how PTMs, including phosphorylation, S-acylation, and ubiquitination, affect the stability, localization, and function of zDHHC enzymes and speculate on possible effects of PTMs that have emerged from larger screening studies. Developing a better understanding of the regulatory effects of PTMs on zDHHC enzymes will provide new insight into the intracellular dynamics of S-acylation and may also highlight novel approaches to modulate S-acylation for clinical gain.

scholarly journals The Role of Packing Defects in the Stability and Function of the Intramembrane Protease GlpG

2017 ◽  
Vol 112 (3) ◽  
pp. 86a
Author(s):  
Ruiqiong Guo ◽  
Zixuan Cang ◽  
Deans Erin ◽  
Guowei Wei ◽  
Heedeok Hong
Keyword(s):  
Packing Defects ◽  
The Stability ◽  
And Function

scholarly journals Role of Choline in Ocular Diseases

2021 ◽  
Vol 22 (9) ◽  
pp. 4733
Author(s):  
Jin-Sun Hwang ◽  
Young-Joo Shin
Keyword(s):  
Parasympathetic Nervous System ◽  
Retinal Hemorrhage ◽  
Ocular Diseases ◽  
Choline Deficiency ◽  
Eye Health ◽  
Development And Differentiation ◽  
Health And Disease ◽  
The Stability ◽  
And Function

Choline is essential for maintaining the structure and function of cells in humans. Choline plays an important role in eye health and disease. It is a precursor of acetylcholine, a neurotransmitter of the parasympathetic nervous system, and it is involved in the production and secretion of tears by the lacrimal glands. It also contributes to the stability of the cells and tears on the ocular surface and is involved in retinal development and differentiation. Choline deficiency is associated with retinal hemorrhage, glaucoma, and dry eye syndrome. Choline supplementation may be effective for treating these diseases.

scholarly journals Widespread Head-to-Head Hydrocarbon Biosynthesis in Bacteria and Role of OleA

2010 ◽  
Vol 76 (12) ◽  
pp. 3850-3862 ◽  
Author(s):  
David J. Sukovich ◽  
Jennifer L. Seffernick ◽  
Jack E. Richman ◽  
Jeffrey A. Gralnick ◽  
Lawrence P. Wackett
Keyword(s):  
Xanthomonas Campestris ◽  
Gene Deletion ◽  
Shewanella Oneidensis ◽  
Fatty Acyl ◽  
Double Bonds ◽  
Acyl Chains ◽  
Hydrocarbon Biosynthesis ◽  
Structural Alignments ◽  
Long Chain

ABSTRACT Previous studies identified the oleABCD genes involved in head-to-head olefinic hydrocarbon biosynthesis. The present study more fully defined the OleABCD protein families within the thiolase, α/β-hydrolase, AMP-dependent ligase/synthase, and short-chain dehydrogenase superfamilies, respectively. Only 0.1 to 1% of each superfamily represents likely Ole proteins. Sequence analysis based on structural alignments and gene context was used to identify highly likely ole genes. Selected microorganisms from the phyla Verucomicrobia, Planctomyces, Chloroflexi, Proteobacteria, and Actinobacteria were tested experimentally and shown to produce long-chain olefinic hydrocarbons. However, different species from the same genera sometimes lack the ole genes and fail to produce olefinic hydrocarbons. Overall, only 1.9% of 3,558 genomes analyzed showed clear evidence for containing ole genes. The type of olefins produced by different bacteria differed greatly with respect to the number of carbon-carbon double bonds. The greatest number of organisms surveyed biosynthesized a single long-chain olefin, 3,6,9,12,15,19,22,25,28-hentriacontanonaene, that contains nine double bonds. Xanthomonas campestris produced the greatest number of distinct olefin products, 15 compounds ranging in length from C28 to C31 and containing one to three double bonds. The type of long-chain product formed was shown to be dependent on the oleA gene in experiments with Shewanella oneidensis MR-1 ole gene deletion mutants containing native or heterologous oleA genes expressed in trans. A strain deleted in oleABCD and containing oleA in trans produced only ketones. Based on these observations, it was proposed that OleA catalyzes a nondecarboxylative thiolytic condensation of fatty acyl chains to generate a β-ketoacyl intermediate that can decarboxylate spontaneously to generate ketones.

scholarly journals The acyltransferase LYCAT controls specific phosphoinositides and related membrane traffic

2017 ◽  
Vol 28 (1) ◽  
pp. 161-172 ◽  
Author(s):  
Leslie N. Bone ◽  
Roya M. Dayam ◽  
Minhyoung Lee ◽  
Nozomu Kono ◽  
Gregory D. Fairn ◽  
...  
Keyword(s):  
Acyl Chain ◽  
Membrane Traffic ◽  
Cell Physiology ◽  
Phosphatidylinositol Synthase ◽  
Lipid Kinases ◽  
Acyl Chains ◽  
And Function ◽  
Phosphatidylinositol 4 ◽  
Phosphatidylinositol 3

Phosphoinositides (PIPs) are key regulators of membrane traffic and signaling. The interconversion of PIPs by lipid kinases and phosphatases regulates their functionality. Phosphatidylinositol (PI) and PIPs have a unique enrichment of 1-stearoyl-2-arachidonyl acyl species; however, the regulation and function of this specific acyl profile remains poorly understood. We examined the role of the PI acyltransferase LYCAT in control of PIPs and PIP-dependent membrane traffic. LYCAT silencing selectively perturbed the levels and localization of phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] and phosphatidylinositol-3-phosphate and the membrane traffic dependent on these specific PIPs but was without effect on phosphatidylinositol-4-phosphate or biosynthetic membrane traffic. The acyl profile of PI(4,5)P2 was selectively altered in LYCAT-deficient cells, whereas LYCAT localized with phosphatidylinositol synthase. We propose that LYCAT remodels the acyl chains of PI, which is then channeled into PI(4,5)P2. Our observations suggest that the PIP acyl chain profile may exert broad control of cell physiology.

scholarly journals Synaptotagmin C2A Loop 2 Mediates Ca2+-dependent SNARE Interactions Essential for Ca2+-triggered Vesicle Exocytosis

2007 ◽  
Vol 18 (12) ◽  
pp. 4957-4968 ◽  
Author(s):  
K. L. Lynch ◽  
R.R.L. Gerona ◽  
E. C. Larsen ◽  
R. F. Marcia ◽  
J. C. Mitchell ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
Membrane Binding ◽  
Binding Surface ◽  
Essential Components ◽  
Vesicle Exocytosis ◽  
Synaptotagmin 1 ◽  
Liposome Fusion ◽  
And Function ◽  
Loop 2

Synaptotagmins contain tandem C2 domains and function as Ca2+ sensors for vesicle exocytosis but the mechanism for coupling Ca2+ rises to membrane fusion remains undefined. Synaptotagmins bind SNAREs, essential components of the membrane fusion machinery, but the role of these interactions in Ca2+-triggered vesicle exocytosis has not been directly assessed. We identified sites on synaptotagmin−1 that mediate Ca2+-dependent SNAP25 binding by zero-length cross-linking. Mutation of these sites in C2A and C2B eliminated Ca2+-dependent synaptotagmin−1 binding to SNAREs without affecting Ca2+-dependent membrane binding. The mutants failed to confer Ca2+ regulation on SNARE-dependent liposome fusion and failed to restore Ca2+-triggered vesicle exocytosis in synaptotagmin-deficient PC12 cells. The results provide direct evidence that Ca2+-dependent SNARE binding by synaptotagmin is essential for Ca2+-triggered vesicle exocytosis and that Ca2+-dependent membrane binding by itself is insufficient to trigger fusion. A structure-based model of the SNARE-binding surface of C2A provided a new view of how Ca2+-dependent SNARE and membrane binding occur simultaneously.

Sign in / Sign up

Export Citation Format

Share Document