scholarly journals Mutations That Affect the Surface Expression of TRPV6 Are Associated with the Upregulation of Serine Proteases in the Placenta of an Infant

2021 ◽  
Vol 22 (23) ◽  
pp. 12694
Author(s):  
Claudia Fecher-Trost ◽  
Karin Wolske ◽  
Christine Wesely ◽  
Heidi Löhr ◽  
Daniel S. Klawitter ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Skeletal Dysplasia ◽  
Serine Proteases ◽  
Calcium Uptake ◽  
Stop Codon ◽  
Surface Expression ◽  
Calcium Deficiency ◽  
Cathepsin G ◽  
Wild Type ◽  
Heterozygous Parent

Recently, we reported a case of an infant with neonatal severe under-mineralizing skeletal dysplasia caused by mutations within both alleles of the TRPV6 gene. One mutation results in an in frame stop codon (R510stop) that leads to a truncated, nonfunctional TRPV6 channel, and the second in a point mutation (G660R) that, surprisingly, does not affect the Ca2+ permeability of TRPV6. We mimicked the subunit composition of the unaffected heterozygous parent and child by coexpressing the TRPV6 G660R and R510stop mutants and combinations with wild type TRPV6. We show that both the G660R and R510stop mutant subunits are expressed and result in decreased calcium uptake, which is the result of the reduced abundancy of functional TRPV6 channels within the plasma membrane. We compared the proteomic profiles of a healthy placenta with that of the diseased infant and detected, exclusively in the latter two proteases, HTRA1 and cathepsin G. Our results implicate that the combination of the two mutant TRPV6 subunits, which are expressed in the placenta of the diseased child, is responsible for the decreased calcium uptake, which could explain the skeletal dysplasia. In addition, placental calcium deficiency also appears to be associated with an increase in the expression of proteases.

scholarly journals Palmitoylation of the Rous Sarcoma Virus Transmembrane Glycoprotein Is Required for Protein Stability and Virus Infectivity

2001 ◽  
Vol 75 (23) ◽  
pp. 11544-11554 ◽  
Author(s):  
Christina Ochsenbauer-Jambor ◽  
David C. Miller ◽  
Charles R. Roberts ◽  
Sung S. Rhee ◽  
Eric Hunter
Keyword(s):  
Plasma Membrane ◽  
Rous Sarcoma Virus ◽  
Double Mutant ◽  
Surface Expression ◽  
Virus Infectivity ◽  
Wild Type ◽  
Membrane Expression ◽  
Rous Sarcoma ◽  
Plasma Membrane Expression ◽  
Sarcoma Virus

ABSTRACT The Rous sarcoma virus (RSV) transmembrane (TM) glycoprotein is modified by the addition of palmitic acid. To identify whether conserved cysteines within the hydrophobic anchor region are the site(s) of palmitoylation, and to determine the role of acylation in glycoprotein function, cysteines at residues 164 and 167 of the TM protein were mutated to glycine (C164G, C167G, and C164G/C167G). In CV-1 cells, palmitate was added to env gene products containing single mutations but was absent in the double-mutant Env. Although mutant Pr95 Env precursors were synthesized with wild-type kinetics, the phenotypes of the mutants differed markedly. Env-C164G had properties similar to those of the wild type, while Env-C167G was degraded faster, and Env containing the double mutant C164G/C167G was very rapidly degraded. Degradation occurred after transient plasma membrane expression. The decrease in steady-state surface expression and increased rate of internalization into endosomes and lysosomes paralleled the decrease in palmitoylation observed for the mutants. The phenotypes of mutant viruses were assessed in avian cells in the context of the pATV8R proviral genome. Virus containing the C164G mutation replicated with wild-type kinetics but exhibited reduced peak reverse transcriptase levels. In contrast, viruses containing either the C167G or the C164G/C167G mutation were poorly infectious or noninfectious, respectively. These phenotypes correlated with different degrees of glycoprotein incorporation into virions. Infectious revertants of the double mutant demonstrated the importance of cysteine-167 for efficient plasma membrane expression and Env incorporation. The observation that both cysteines within the membrane-spanning domain are accessible for acylation has implications for the topology of this region, and a model is proposed.

Abstract 126: Gene Deletion of Dipeptidyl Peptidase I Reduces Myocyte Loss and Preserves Cardiac Function After Myocardial Ischemia-Reperfusion Injury

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Zhao Qi ◽  
Mikhail Kolpakov ◽  
Bahman Hooshdaran ◽  
Khadija Rafiq ◽  
Xinji Guo ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Cardiac Function ◽  
Reperfusion Injury ◽  
Cardiac Remodeling ◽  
Serine Proteases ◽  
Gene Deletion ◽  
Cathepsin G ◽  
Wild Type ◽  
Myocyte Apoptosis

Introduction and Hypothesis: Chronic inflammation predisposes tissue to adverse cardiac remodeling and contributes to heart failure (HF) progression. The mechanisms whereby inflammation contributes to cardiac remodeling after cardiac injury has largely focused on action of reactive oxygen species and cytokines/chemokines and their role on myocyte growth and extracellular matrix (ECM) remodeling. However, the role of inflammatory proteases on myocyte loss and adverse cardiac remodeling has not been studied and are the focus of this study. Methods and Results: We subjected wild type and mice lacking Dipeptidyl peptidase I (DPPI), a lysosomal enzyme involved in the cleavage and activation of major inflammatory serine proteases, to myocardial ischemia for 30 min followed by reperfusion for 24hrs (IRI) and assessed the role of DPPI gene deletion on inflammatory proteases activation, myocyte apoptosis and cardiac remodeling and function. DPPI KO mice show markedly reduced inflammatory serine protease activity in response to myocardial IRI compared to wild type mice. DPPI deletion also markedly reduced myocyte apoptosis, limited infarct size and improved cardiac function in response to IRI. The role of inflammatory serine proteases in cardiac remodeling was further demonstrated after in-vivo cardiac transfer of cathepsin G, a neutrophil derived serine protease that has been shown to induce myocyte death in-vitro. Mice with cathepsin G injection for 5 days show increased interstitial collagen degradation and myocyte apoptosis and presented cardiac dilatation and contractile dysfunction. Conclusions: These findings reveal the role of DPPI as a key mediator of postischemic/reperfusion injury and show that inflammatory derived proteases contribute to the pathological cardiac remodeling and dysfunction.

A Leu262Pro mutation in the integrin β3 subunit results in an αIIb-β3 complex that binds fibrin but not fibrinogen

Blood ◽  
2000 ◽  
Vol 96 (1) ◽  
pp. 161-169 ◽  
Author(s):  
Christopher M. Ward ◽  
Anita S. Kestin ◽  
Peter J. Newman
Keyword(s):  
Stop Codon ◽  
Premature Stop Codon ◽  
Surface Expression ◽  
Fibrin Clot ◽  
Wild Type ◽  
Clot Retraction ◽  
Fibrinogen Receptor ◽  
Fibrinogen Binding ◽  
293 Cells ◽  
Platelet Disorder

Abstract Platelet retraction of a fibrin clot is mediated by the platelet fibrinogen receptor, IIbβ3. In certain forms of the inherited platelet disorder, Glanzmann thrombasthenia (GT), mutant IIbβ3 may interact normally with fibrin yet fail to support fibrinogen-dependent aggregation. We describe a patient (LD) with such a form of GT. Platelets from LD supported normal clot retraction but failed to bind fibrinogen. Platelet analysis using flow cytometry and immunoblotting showed reduced but clearly detectable IIbβ3, findings consistent with type II GT. Genotyping of LD revealed 2 novel β3 mutations: a deletion of nucleotides 867 to 868, resulting in a premature stop codon at amino acid residue 267, and a T883C missense mutation, resulting in a leucine (Leu) 262-to-proline (Pro) substitution. Leu262 is highly conserved among β integrin subunits and lies within an intrachain loop implicated in subunit association. Leu262Proβ3 cotransfected with wild-type IIb into COS-7 cells showed delayed intracellular maturation and reduced surface expression of easily dissociable complexes. In human embryonic kidney 293 cells, Leu262Proβ3 formed a complex with endogenous av and retracted fibrin clots similarly to wild-type β3. The same cells, however, were unable to bind immobilized fibrinogen. The molecular requirements for IIbβ3 to interact with fibrin compared with fibrinogen, therefore, appear to differ. The region surrounding β3 Leu262 may maintain β3 in a fibrinogen-binding, competent form, but it appears not to be required for receptor interactions with fibrin.

A Leu262Pro mutation in the integrin β3 subunit results in an αIIb-β3 complex that binds fibrin but not fibrinogen

Blood ◽  
2000 ◽  
Vol 96 (1) ◽  
pp. 161-169 ◽  
Author(s):  
Christopher M. Ward ◽  
Anita S. Kestin ◽  
Peter J. Newman
Keyword(s):  
Stop Codon ◽  
Premature Stop Codon ◽  
Surface Expression ◽  
Fibrin Clot ◽  
Wild Type ◽  
Clot Retraction ◽  
Fibrinogen Receptor ◽  
Fibrinogen Binding ◽  
293 Cells ◽  
Platelet Disorder

Platelet retraction of a fibrin clot is mediated by the platelet fibrinogen receptor, IIbβ3. In certain forms of the inherited platelet disorder, Glanzmann thrombasthenia (GT), mutant IIbβ3 may interact normally with fibrin yet fail to support fibrinogen-dependent aggregation. We describe a patient (LD) with such a form of GT. Platelets from LD supported normal clot retraction but failed to bind fibrinogen. Platelet analysis using flow cytometry and immunoblotting showed reduced but clearly detectable IIbβ3, findings consistent with type II GT. Genotyping of LD revealed 2 novel β3 mutations: a deletion of nucleotides 867 to 868, resulting in a premature stop codon at amino acid residue 267, and a T883C missense mutation, resulting in a leucine (Leu) 262-to-proline (Pro) substitution. Leu262 is highly conserved among β integrin subunits and lies within an intrachain loop implicated in subunit association. Leu262Proβ3 cotransfected with wild-type IIb into COS-7 cells showed delayed intracellular maturation and reduced surface expression of easily dissociable complexes. In human embryonic kidney 293 cells, Leu262Proβ3 formed a complex with endogenous av and retracted fibrin clots similarly to wild-type β3. The same cells, however, were unable to bind immobilized fibrinogen. The molecular requirements for IIbβ3 to interact with fibrin compared with fibrinogen, therefore, appear to differ. The region surrounding β3 Leu262 may maintain β3 in a fibrinogen-binding, competent form, but it appears not to be required for receptor interactions with fibrin.

scholarly journals Structure-function relationship of serine protease-protein inhibitor interaction.

2001 ◽  
Vol 48 (2) ◽  
pp. 419-428 ◽  
Author(s):  
J Otlewski ◽  
M Jaskólski ◽  
O Buczek ◽  
T Cierpicki ◽  
H Czapińska ◽  
...  
Keyword(s):  
High Resolution ◽  
Structure Function ◽  
Serine Proteases ◽  
Cathepsin G ◽  
Wild Type ◽  
Stability Parameters ◽  
X Ray ◽  
Structure Function Relationship ◽  
Function Relationship ◽  
Relationship Of

We report our progress in understanding the structure-function relationship of the interaction between protein inhibitors and several serine proteases. Recently, we have determined high resolution solution structures of two inhibitors Apis mellifera chymotrypsin inhibitor-1 (AMCI-I) and Linum usitatissimum trypsin inhibitor (LUTI) in the free state and an ultra high resolution X-ray structure of BPTI. All three inhibitors, despite totally different scaffolds, contain a solvent exposed loop of similar conformation which is highly complementary to the enzyme active site. Isothermal calo- rimetry data show that the interaction between wild type BPTI and chymotrypsin is entropy driven and that the enthalpy component opposes complex formation. Our research is focused on extensive mutagenesis of the four positions from the protease binding loop of BPTI: P1, P1', P3, and P4. We mutated these residues to different amino acids and the variants were characterized by determination of the association constants, stability parameters and crystal structures of protease-inhibitor complexes. Accommodation of the P1 residue in the S1 pocket of four proteases: chymotrypsin, trypsin, neutrophil elastase and cathepsin G was probed with 18 P1 variants. High resolution X-ray structures of ten complexes between bovine trypsin and P1 variants of BPTI have been determined and compared with the cognate P1 Lys side chain. Mutations of the wild type Ala16 (P1') to larger side chains always caused a drop of the association constant. According to the crystal structure of the Leu16 BPTI-trypsin complex, introduction of the larger residue at the P1' position leads to steric conflicts in the vicinity of the mutation. Finally, mutations at the P4 site allowed an improvement of the association with several serine proteases involved in blood clotting. Conversely, introduction of Ser, Val, and Phe in place of Gly12 (P4) had invariably a destabilizing effect on the complex with these proteases.

scholarly journals Inhibition of endocytosis causes phosphorylation (S256)-independent plasma membrane accumulation of AQP2

2004 ◽  
Vol 286 (2) ◽  
pp. F233-F243 ◽  
Author(s):  
Hua Lu ◽  
Tian-Xiao Sun ◽  
Richard Bouley ◽  
Karen Blackburn ◽  
Margaret McLaughlin ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Collecting Duct ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Wild Type ◽  
Independent Manner ◽  
Cell Surface Biotinylation ◽  
Extensive Cell ◽  
Medullary Collecting Duct

Inhibition of clathrin-mediated endocytosis by expression of a GTPase-deficient dynamin mutant (dynamin-2/K44A) for 16 h results in an accumulation of plasma membrane aquaporin-2 (AQP2) in epithelial cells stably transfected with wild-type AQP2. We now show a similar effect of K44A dynamin in LLC-PK1 cells transfected with an S256 phosphorylation-deficient AQP2 mutant, AQP2(S256A), and in AQP2-transfected inner medullary collecting duct (IMCD) cells. More acute blockade of endocytosis in these cells with the cholesterol-depleting agent methyl-β-cyclodextrin (mβCD; 10 mM) resulted in a rapid and extensive cell-surface accumulation of both wild-type AQP2 and AQP2 (S256A) within 15 min after treatment. This effect was similar to that induced by treatment of the cells with vasopressin. Blockade of endocytosis by mβCD was confirmed using quantitative analysis of FITC-dextran uptake and AQP2 membrane insertion was verified by cell-surface biotinylation. These data indicate that AQP2 recycles constitutively and rapidly between intracellular stores and the cell surface in LLC-PK1 and IMCD cells. The constitutive trafficking process is not dependent on phosphorylation of the serine-256 residue of AQP2, which is, however, an essential step for regulated vasopressin/cAMP-mediated translocation of AQP2. Our data show that rapid and extensive plasma membrane accumulation of AQP2 can occur in a vasopressin receptor (V2R)- and phosphorylation-independent manner, pointing to a potential means of bypassing the mutated V2R in X-linked nephrogenic diabetes insipidus to achieve cell surface expression of AQP2.

Olfactomedin 4 Down-Regulates Neutrophil Killing of Gram-Positive and Gram-Negative Bacteria.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3777-3777
Author(s):  
Wenli Liu ◽  
Ming Yan ◽  
Yueqin Liu ◽  
William G Coleman ◽  
Griffin P. Rodgers
Keyword(s):  
Neutrophil Elastase ◽  
Serine Proteases ◽  
Cathepsin G ◽  
Proteinase 3 ◽  
Gram Negative Bacteria ◽  
Wild Type ◽  
Gram Negative ◽  
Cathepsin C ◽  
E Coli ◽  
Deficient Mice

Abstract Abstract 3777 Introduction: Olfactomedin 4 (OLFM4) is a member of olfactomedin-related glycoprotein family, which is specifically expressed in neutrophils and gastrointestinal tract. OLFM4 expression is upregulated in gastrointestinal cancer and inflammatory diseases such as chronic inflammatory bowel disease and Helicobacter pylori infection. It has been shown that OLFM4 is a target gene of NF-kB and Notch pathways and that OLFM4 down-regulates innate immunity to H. pylori infection. However, its potential biological functions in neutrophils still remain to be defined. The goal of this study is to determine whether OLFM4 is involved in the bactericidal activity of neutrophils using an OLFM4 deficient mouse model. Results: 1. OLFM4 expression in neutrophils is upregulated in response to Staphylocococus aureus (Gram positive) and Escherichia coli (Gram negative) bacteria. 2. We have shown that neutrophils from OLFM4 deficient mice have increased intracellular killing of S. aureus and E. coli bacteria in vitro. 3. The OLFM4 deficient mice displayed enhanced bacterial clearance in vivo when the mice were challenged with intra-peritoneal injection of S. aureus and E. coli. 4. To elucidate the molecular mechanisms that mediate these effects, we performed a yeast 2-hybrid screen and found that OLFM4 interacts with cathepsin C (dipeptidyl peptidase I or DPPI), a lysosomal cysteine protease that has a degraditive function as an exopeptidase and is essential for activation of neutrophil granule-associated serine proteases including neutrophil elastase, cathepsin G and proteinase 3. The direct association of OLFM4 with cathepsin C was confirmed in human primary neutrophils. 4. We have demonstrated that OLFM4 is a direct substrate of DPPI and inhibits DPPI activity in transfected 293T cells. 5. The cathepsin C activity in neutrophils from OLFM4 deficient mice was significantly higher than that in neutrophils from wild-type littermate mice in the absence or presence of bacterial infection, suggesting that OLFM4 is an endogenous inhibitor of cathepsin C in neutrophils. 6. We have also demonstrated increased activities of neutrophil elastase, cathepsin G and proteinase 3 (whose processing and maturity require cathepsin C activity) in OLFM4 deficient neutrophils compared with wild-type neutrophils. 7. Activation of NADPH oxidase, myeloperoxidase (MPO) activity, and neutrophil phagocytosis were not altered in OLFM4 deficient neutrophils compared with wild-type neutrophils. Conclusion: These results suggest that OLFM4 is an important regulator of neutrophil bacterial killing activity via negative regulation of cathepsin C activity and its down stream granule-associated serine proteases. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Nonrecombinant meiosis I nondisjunction in Saccharomyces cerevisiae induced by tRNA ochre suppressors.

Genetics ◽  
1989 ◽  
Vol 123 (1) ◽  
pp. 81-95 ◽  
Author(s):  
E J Louis ◽  
J E Haber
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitotic Chromosome ◽  
Stop Codon ◽  
Fold Increase ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Nonsense Mutations ◽  
Chromosome Iii ◽  
Meiosis I ◽  
Chromosome Nondisjunction

Abstract The presence of the tRNA ochre suppressors SUP11 and SUP5 is found to induce meiosis I nondisjunction in the yeast Saccharomyces cerevisiae. The induction increases with increasing dosage of the suppressor and decreases in the presence of an antisuppressor. The effect is independent of the chromosomal location of SUP11. Each of five different chromosomes monitored exhibited nondisjunction at frequencies of 0.1%-1.1% of random spores, which is a 16-160-fold increase over wild-type levels. Increased nondisjunction is reflected by a marked increase in tetrads with two and zero viable spores. In the case of chromosome III, for which a 50-cM map interval was monitored, the resulting disomes are all in the parental nonrecombinant configuration. Recombination along chromosome III appears normal both in meioses that have no nondisjunction and in meioses for which there was nondisjunction of another chromosome. We propose that a proportion of one or more proteins involved in chromosome pairing, recombination or segregation are aberrant due to translational read-through of the normal ochre stop codon. Hygromycin B, an antibiotic that can suppress nonsense mutations via translational read-through, also induces nonrecombinant meiosis I nondisjunction. Increases in mistranslation, therefore, increase the production of aneuploids during meiosis. There was no observable effect of SUP11 on mitotic chromosome nondisjunction; however some disomes caused SUP11 ade2-ochre strains to appear white or red, instead of pink.

scholarly journals Low ABA concentration promotes root growth and hydrotropism through relief of ABA INSENSITIVE 1-mediated inhibition of plasma membrane H+-ATPase 2

2021 ◽  
Vol 7 (12) ◽  
pp. eabd4113
Author(s):  
Rui Miao ◽  
Wei Yuan ◽  
Yue Wang ◽  
Irene Garcia-Maquilon ◽  
Xiaolin Dang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Root Growth ◽  
Experimental System ◽  
Aba Signaling ◽  
Wild Type ◽  
Normal Medium ◽  
C Terminus ◽  
Quadruple Mutant ◽  
Aba Insensitive ◽  
Aba Receptors

The hab1-1abi1-2abi2-2pp2ca-1 quadruple mutant (Qabi2-2) seedlings lacking key negative regulators of ABA signaling, namely, clade A protein phosphatases type 2C (PP2Cs), show more apoplastic H+ efflux in roots and display an enhanced root growth under normal medium or water stress medium compared to the wild type. The presence of low ABA concentration (0.1 micromolar), inhibiting PP2C activity via monomeric ABA receptors, enhances root apoplastic H+ efflux and growth of the wild type, resembling the Qabi2-2 phenotype in normal medium. Qabi2-2 seedlings also demonstrate increased hydrotropism compared to the wild type in obliquely-oriented hydrotropic experimental system, and asymmetric H+ efflux in root elongation zone is crucial for root hydrotropism. Moreover, we reveal that Arabidopsis ABA-insensitive 1, a key PP2C in ABA signaling, interacts directly with the C terminus of Arabidopsis plasma membrane H+-dependent adenosine triphosphatase 2 (AHA2) and dephosphorylates its penultimate threonine residue (Thr947), whose dephosphorylation negatively regulates AHA2.

scholarly journals Elimination of Introns at the Drosophila suppressor-of-forked Locus by P-Element-Mediated Gene Conversion Shows That an RNA Lacking a Stop Codon is Dispensable

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 345-351
Author(s):  
Carol J Williams ◽  
Kevin O'Hare
Keyword(s):  
X Chromosome ◽  
Stop Codon ◽  
Alternative Polyadenylation ◽  
Gene Replacement ◽  
P Element ◽  
Wild Type ◽  
Genomic Location ◽  
Chromosomal Breaks ◽  
White Locus ◽  
Cleavage Stimulation Factor

Abstract The suppressor of forked [su(f)] locus affects the phenotype of mutations caused by transposable element insertions at unlinked loci. It encodes a putative 84-kD protein with homology to two proteins involved in mRNA 3′ end processing; the product of the yeast RNA14 gene and the 77-kD subunit of human cleavage stimulation factor. Three su(f) mRNAs are produced by alternative polyadenylation. The 2. 6 and 2.9-kb mRNAs encode the same 84-kD protein while a 1.3-kb RNA, which terminates within the fourth intron, is unusual in having no stop codon. Using P-element-mediated gene replacement we have copied sequences from a transformation construct into the su(f) gene creating a su(f) allele at the normal genomic location that lacks the first five introns. This allele is viable and appears wild type for su(f) function, demonstrating that the 1.3-kb RNA and the sequences contained within the deleted introns are dispensable for su(f) function. Compared with studies on gene replacement at the white locus, chromosomal breaks at su(f) appear to be less efficiently repaired from ectopic sites, perhaps because of the location of su(f) at the euchromatin/heterochromatin boundary on the X chromosome.

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