scholarly journals Mice with defects in HB-EGF ectodomain shedding show severe developmental abnormalities

2003 ◽  
Vol 163 (3) ◽  
pp. 469-475 ◽  
Author(s):  
Satoru Yamazaki ◽  
Ryo Iwamoto ◽  
Kazuko Saeki ◽  
Masanori Asakura ◽  
Seiji Takashima ◽  
...  
Keyword(s):  
Heart Valves ◽  
Transmembrane Domain ◽  
Severe Heart Failure ◽  
Gene Replacement ◽  
Soluble Form ◽  
Ectodomain Shedding ◽  
Heparin Binding ◽  
Developmental Abnormalities ◽  
Targeted Gene Replacement

Heparin-binding EGF-like growth factor (HB-EGF) is first synthesized as a membrane-anchored form (proHB-EGF), and its soluble form (sHB-EGF) is released by ectodomain shedding from proHB-EGF. To examine the significance of proHB-EGF processing in vivo, we generated mutant mice by targeted gene replacement, expressing either an uncleavable form (HBuc) or a transmembrane domain–truncated form (HBΔtm) of the molecule. HBuc/uc mice developed severe heart failure and enlarged heart valves, phenotypes similar to those in proHB-EGF null mice. On the other hand, mice carrying HBΔtm exhibited severe hyperplasia in both skin and heart. These results indicate that ectodomain shedding of proHB-EGF is essential for HB-EGF function in vivo, and that this process requires strict control.

Scanning Tunneling Microscopy and Atomic Force Microscopy of Enzymes and Enzyme Complexes

1990 ◽  
Vol 48 (3) ◽  
pp. 174-175
Author(s):  
Ronald D. Edstrom ◽  
Xiuru Yang ◽  
Mary E. Gurnack ◽  
Marcia A. Miller ◽  
Rui Yang ◽  
...  
Keyword(s):  
Cell Biology ◽  
Inorganic Ions ◽  
Bulk Liquid ◽  
Soluble Form ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Metabolic Channeling ◽  
Simplistic Notion ◽  
Soluble Enzymes

Many of the questions in biochemistry and cell biology are concerned with the relationships of proteins and other macromolecules in complex arrays which are responsible for carrying out metabolic sequences. The simplistic notion that the enzymes we isolate in soluble form from the cytoplasm were also soluble in vivo is being replaced by the concept that these enzymes occur in organized systems within the cell. In this newer view, the cytoplasm is organized and the “soluble enzymes” are in fact fixed in the cellular space and the only soluble components of the cell are small metabolites, inorganic ions etc. Further support for the concept of metabolic organization is provided by the evidence of metabolic channeling. It has been shown that for some metabolic pathways, the intermediates are not in free diffusion equilibrium with the bulk liquid in the cell but are passed along, more or less directly, from one enzyme to the next.

In vivo repopulation of tissue engineered heart valves

2010 ◽  
Vol 58 (S 01) ◽  
Author(s):  
PM Dohmen ◽  
A Lembcke ◽  
S Holinski ◽  
JP Braun ◽  
W Konertz
Keyword(s):  
Heart Valves ◽  
Tissue Engineered Heart Valves

One Year In-Vivo Functionality of Transvenously Implanted Tissue-Engineered Pulmonary Heart Valves in Sheep

2016 ◽  
Vol 64 (S 02) ◽  
Author(s):  
H. Spriestersbach ◽  
L. Bruder ◽  
B. Sanders ◽  
E. Fioretta ◽  
D. O h-Icí ◽  
...  
Keyword(s):  
Heart Valves ◽  
One Year

The angiogenic factor CCN1 promotes re-endothelialization of decellularized pulmonary heart valves in vivo

2008 ◽  
Vol 56 (S 1) ◽  
Author(s):  
A Hilfiker ◽  
M Suprunov ◽  
D Hilfiker-Kleiner ◽  
I Tudorache ◽  
S Cebotari ◽  
...  
Keyword(s):  
Heart Valves ◽  
Angiogenic Factor

Novel concatameric heparin-binding peptides reverse heparin and low-molecular-weight heparin anticoagulant activities in patient plasma in vitro and in rats in vivo

Blood ◽  
2004 ◽  
Vol 103 (4) ◽  
pp. 1356-1363 ◽  
Author(s):  
Barbara P. Schick ◽  
David Maslow ◽  
Adrianna Moshinski ◽  
James D. San Antonio
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Tandem Repeats ◽  
Factor Xa ◽  
Low Molecular Weight ◽  
Heparin Binding ◽  
High Affinity ◽  
Binding Peptides

Abstract Patients given unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) for prophylaxis or treatment of thrombosis sometimes suffer serious bleeding. We showed previously that peptides containing 3 or more tandem repeats of heparin-binding consensus sequences have high affinity for LMWH and neutralize LMWH (enoxaparin) in vivo in rats and in vitro in citrate. We have now modified the (ARKKAAKA)n tandem repeat peptides by cyclization or by inclusion of hydrophobic tails or cysteines to promote multimerization. These peptides exhibit high-affinity binding to LMWH (dissociation constant [Kd], ≈ 50 nM), similar potencies in neutralizing anti–Factor Xa activity of UFH and enoxaparin added to normal plasma in vitro, and efficacy equivalent to or greater than protamine. Peptide (ARKKAAKA)3VLVLVLVL was most effective in all plasmas from enoxaparin-treated patients, and was 4- to 20-fold more effective than protamine. Several other peptide structures were effective in some patients' plasmas. All high-affinity peptides reversed inhibition of thrombin-induced clot formation by UFH. These peptides (1 mg/300 g rat) neutralized 1 U/mL anti–Factor Xa activity of enoxaparin in rats within 1 to 2 minutes. Direct blood pressure and heart rate measurements showed little or no hemodynamic effect. These heparin-binding peptides, singly or in combination, are potential candidates for clinical reversal of UFH and LMWH in humans.

scholarly journals Syndecan Transmembrane Domain Specifically Regulates Downstream Signaling Events of the Transmembrane Receptor Cytoplasmic Domain

2021 ◽  
Vol 22 (15) ◽  
pp. 7918
Author(s):  
Jisun Hwang ◽  
Bohee Jang ◽  
Ayoung Kim ◽  
Yejin Lee ◽  
Joonha Lee ◽  
...  
Keyword(s):  
Transmembrane Domain ◽  
Growth Factor Receptor ◽  
Cytoplasmic Domain ◽  
Nih3t3 Cells ◽  
C Elegans ◽  
Downstream Signaling ◽  
Downstream Effectors ◽  
Signaling Events

Despite the known importance of the transmembrane domain (TMD) of syndecan receptors in cell adhesion and signaling, the molecular basis for syndecan TMD function remains unknown. Using in vivo invertebrate models, we found that mammalian syndecan-2 rescued both the guidance defects in C. elegans hermaphrodite-specific neurons and the impaired development of the midline axons of Drosophila caused by the loss of endogenous syndecan. These compensatory effects, however, were reduced significantly when syndecan-2 dimerization-defective TMD mutants were introduced. To further investigate the role of the TMD, we generated a chimera, 2eTPC, comprising the TMD of syndecan-2 linked to the cytoplasmic domain of platelet-derived growth factor receptor (PDGFR). This chimera exhibited SDS-resistant dimer formation that was lost in the corresponding dimerization-defective syndecan-2 TMD mutant, 2eT(GL)PC. Moreover, 2eTPC specifically enhanced Tyr 579 and Tyr 857 phosphorylation in the PDGFR cytoplasmic domain, while the TMD mutant failed to support such phosphorylation. Finally, 2eTPC, but not 2eT(GL)PC, induced phosphorylation of Src and PI3 kinase (known downstream effectors of Tyr 579 phosphorylation) and promoted Src-mediated migration of NIH3T3 cells. Taken together, these data suggest that the TMD of a syndecan-2 specifically regulates receptor cytoplasmic domain function and subsequent downstream signaling events controlling cell behavior.

scholarly journals Refining Genotypes and Phenotypes in KCNA2-Related Neurological Disorders

2021 ◽  
Vol 22 (6) ◽  
pp. 2824
Author(s):  
Jan H. Döring ◽  
Julian Schröter ◽  
Jerome Jüngling ◽  
Saskia Biskup ◽  
Kerstin A. Klotz ◽  
...  
Keyword(s):  
Neurological Disorders ◽  
Transmembrane Domain ◽  
Potassium Conductance ◽  
Epileptic Encephalopathy ◽  
Clinical Spectrum ◽  
The Novel ◽  
Developmental Abnormalities ◽  
Pathogenic Variants ◽  
Infantile Seizures ◽  
Early Developmental

Pathogenic variants in KCNA2, encoding for the voltage-gated potassium channel Kv1.2, have been identified as the cause for an evolving spectrum of neurological disorders. Affected individuals show early-onset developmental and epileptic encephalopathy, intellectual disability, and movement disorders resulting from cerebellar dysfunction. In addition, individuals with a milder course of epilepsy, complicated hereditary spastic paraplegia, and episodic ataxia have been reported. By analyzing phenotypic, functional, and genetic data from published reports and novel cases, we refine and further delineate phenotypic as well as functional subgroups of KCNA2-associated disorders. Carriers of variants, leading to complex and mixed channel dysfunction that are associated with a gain- and loss-of-potassium conductance, more often show early developmental abnormalities and an earlier onset of epilepsy compared to individuals with variants resulting in loss- or gain-of-function. We describe seven additional individuals harboring three known and the novel KCNA2 variants p.(Pro407Ala) and p.(Tyr417Cys). The location of variants reported here highlights the importance of the proline(405)–valine(406)–proline(407) (PVP) motif in transmembrane domain S6 as a mutational hotspot. A novel case of self-limited infantile seizures suggests a continuous clinical spectrum of KCNA2-related disorders. Our study provides further insights into the clinical spectrum, genotype–phenotype correlation, variability, and predicted functional impact of KCNA2 variants.

scholarly journals A Novel Golgi Membrane Protein Is a Partner of the ARF Exchange Factors Gea1p and Gea2p

2003 ◽  
Vol 14 (6) ◽  
pp. 2357-2371 ◽  
Author(s):  
Sophie Chantalat ◽  
Rëgis Courbeyrette ◽  
Francesca Senic-Matuglia ◽  
Catherine L. Jackson ◽  
Bruno Goud ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Protein Trafficking ◽  
Transmembrane Domain ◽  
Integral Membrane Protein ◽  
Membrane Dynamics ◽  
General Interest ◽  
Single Mutation ◽  
Golgi Membrane ◽  
Nucleotide Exchange

The Sec7 domain guanine nucleotide exchange factors (GEFs) for the GTPase ARF are highly conserved regulators of membrane dynamics and protein trafficking. The interactions of large ARF GEFs with cellular membranes for localization and/or activation are likely to participate in regulated recruitment of ARF and effectors. However, these interactions remain largely unknown. Here we characterize Gmh1p, the first Golgi transmembrane-domain partner of any of the high-molecular-weight ARF-GEFs. Gmh1p is an evolutionarily conserved protein. We demonstrate molecular interaction between the yeast Gmh1p and the large ARF-GEFs Gea1p and Gea2p. This interaction involves a domain of Gea1p and Gea2p that is conserved in the eukaryotic orthologues of the Gea proteins. A single mutation in a conserved amino acid residue of this domain is sufficient to abrogate the interaction, whereas the overexpression of Gmh1p can compensate in vivo defects caused by mutations in this domain. We show that Gmh1p is an integral membrane protein that localizes to the early Golgi in yeast and in human HeLa cells and cycles through the ER. Hence, we propose that Gmh1p acts as a positive Golgi-membrane partner for Gea function. These results are of general interest given the evolutionary conservation of both ARF-GEFs and the Gmh proteins.

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