scholarly journals Structure of Mycobacterium tuberculosis Cya, an evolutionary ancestor of the mammalian membrane adenylyl cyclases

2021 ◽  
Author(s):  
Ved Mehta ◽  
Basavraj Khanppnavar ◽  
Dina Schuster ◽  
Irene Vercellino ◽  
Angela Kosturanova ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Catalytic Activity ◽  
Adenylyl Cyclase ◽  
Catalytic Domain ◽  
Transmembrane Domain ◽  
Vital Role ◽  
Cytosolic Side ◽  
Tm Domain ◽  
And Function

AbstractMycobacterium tuberculosis adenylyl cyclase (AC) Cya is an evolutionary ancestor of the mammalian membrane ACs and a model system for studies of their structure and function. Although the vital role of ACs in cellular signaling is well established, the function of their transmembrane (TM) regions remains unknown. Here we describe the cryo-EM structure of Cya bound to a stabilizing nanobody at 3.6 Å resolution. The TM helices 1-5 form a structurally conserved domain that facilitates the assembly of the helical and catalytic domains. The TM region contains discrete pockets accessible from the extracellular and cytosolic side of the membrane. Neutralization of the negatively charged extracellular pocket Ex1 destabilizes the cytosolic helical domain and reduces the catalytic activity of the enzyme. The TM domain acts as a functional component of Cya, guiding the assembly of the catalytic domain and providing the means for direct regulation of catalytic activity in response to extracellular ligands.One-Sentence SummaryCryo-EM structure of M. tuberculosis adenylyl cyclase Cya provides clues to the role of its transmembrane domain

scholarly journals Functional characterization of the non-catalytic ectodomains of the nucleotide pyrophosphatase/phosphodiesterase NPP1

2003 ◽  
Vol 371 (2) ◽  
pp. 321-330 ◽  
Author(s):  
Rik GIJSBERS ◽  
Hugo CEULEMANS ◽  
Mathieu BOLLEN
Keyword(s):  
Catalytic Activity ◽  
Catalytic Domain ◽  
Transmembrane Domain ◽  
Functional Characterization ◽  
Structure Stability ◽  
Subunit Structure ◽  
Terminal Domain ◽  
Nucleotide Pyrophosphatase ◽  
Domain Truncation ◽  
And Function

The ubiquitous nucleotide pyrophosphatases/phosphodiesterases NPP1–3 consist of a short intracellular N-terminal domain, a single transmembrane domain and a large extracellular part, comprising two somatomedin-B-like domains, a catalytic domain and a poorly defined C-terminal domain. We show here that the C-terminal domain of NPP1–3 is structurally related to a family of DNA/RNA non-specific endonucleases. However, none of the residues that are essential for catalysis by the endonucleases are conserved in NPP1–NPP3, suggesting that the nuclease-like domain of NPP1–3 does not represent a second catalytic domain. Truncation analysis revealed that the nuclease-like domain of NPP1 is required for protein stability, for the targeting of NPP1 to the plasma membrane and for the expression of catalytic activity. We also demonstrate that 16 conserved cysteines in the somatomedin-B-like domains of NPP1, in concert with two flanking cysteines, mediate the dimerization of NPP1. The K173Q polymorphism of NPP1, which maps to the second somatomedin-B-like domain and has been associated with the aetiology of insulin resistance, did not affect the dimerization or catalytic activity of NPP1, and did not endow NPP1 with an affinity for the insulin receptor. Our data suggest that the non-catalytic ectodomains contribute to the subunit structure, stability and function of NPP1–3.

scholarly journals The Conserved Positive Charge in the Transmembrane Domain of HIV Gp41 Contributes to Its Intrinsic Preference for Trimerization

2019 ◽  
Author(s):  
Timothy Reichart ◽  
Daniel Leaman ◽  
Daniel Sands ◽  
Michael Zwick ◽  
Philip Dawson
Keyword(s):  
Hiv Infection ◽  
Positive Charge ◽  
Transmembrane Domain ◽  
Structure And Function ◽  
Model Membranes ◽  
Viral Membrane ◽  
Glycoprotein Gp41 ◽  
Tm Domain ◽  
And Function

The transmembrane (TM) domain of HIV glycoprotein gp41 anchors the envelope (Env) spike in the viral membrane and is highly conserved. The mid-span arginine 696 is particularly conserved, and the only other residue found in this position is lysine. Seeking to examine the role of this conserved positive charge in the structure and function of the gp41 TM domain, we synthesized a series of peptides corresponding to this region. Analysis of the peptides in a previously validated fluorescence assay in model membranes showed that the native TM domain is trimeric. Peptides in which the intramembrane arginine was mutated to alanine showed significantly lower trimerization propensity. In contrast, this mutation in the context of infectious pseudovirus caused only modest decreases in viral stability and infectivity. We propose a model to explain the importance of this charge to gp41 structure and to HIV infection.

scholarly journals The Conserved Positive Charge in the Transmembrane Domain of HIV Gp41 Contributes to Its Intrinsic Preference for Trimerization

2020 ◽  
Author(s):  
Timothy Reichart ◽  
Daniel Leaman ◽  
Daniel Sands ◽  
Michael Zwick ◽  
Philip Dawson
Keyword(s):  
Hiv Infection ◽  
Positive Charge ◽  
Transmembrane Domain ◽  
Structure And Function ◽  
Model Membranes ◽  
Viral Membrane ◽  
Glycoprotein Gp41 ◽  
Tm Domain ◽  
And Function

The transmembrane (TM) domain of HIV glycoprotein gp41 anchors the envelope (Env) spike in the viral membrane and is highly conserved. The mid-span arginine 696 is particularly conserved, and the only other residue found in this position is lysine. Seeking to examine the role of this conserved positive charge in the structure and function of the gp41 TM domain, we synthesized a series of peptides corresponding to this region. Analysis of the peptides in a previously validated fluorescence assay in model membranes showed that the native TM domain is trimeric. Peptides in which the intramembrane arginine was mutated to alanine showed significantly lower trimerization propensity. In contrast, this mutation in the context of infectious pseudovirus caused only modest decreases in viral stability and infectivity. We propose a model to explain the importance of this charge to gp41 structure and to HIV infection.

scholarly journals The Conserved Positive Charge in the Transmembrane Domain of HIV Gp41 Contributes to Its Intrinsic Preference for Trimerization

2020 ◽  
Author(s):  
Timothy Reichart ◽  
Daniel Leaman ◽  
Daniel Sands ◽  
Michael Zwick ◽  
Philip Dawson
Keyword(s):  
Hiv Infection ◽  
Positive Charge ◽  
Transmembrane Domain ◽  
Structure And Function ◽  
Model Membranes ◽  
Viral Membrane ◽  
Glycoprotein Gp41 ◽  
Tm Domain ◽  
And Function

The transmembrane (TM) domain of HIV glycoprotein gp41 anchors the envelope (Env) spike in the viral membrane and is highly conserved. The mid-span arginine 696 is particularly conserved, and the only other residue found in this position is lysine. Seeking to examine the role of this conserved positive charge in the structure and function of the gp41 TM domain, we synthesized a series of peptides corresponding to this region. Analysis of the peptides in a previously validated fluorescence assay in model membranes showed that the native TM domain is trimeric. Peptides in which the intramembrane arginine was mutated to alanine showed significantly lower trimerization propensity. In contrast, this mutation in the context of infectious pseudovirus caused only modest decreases in viral stability and infectivity. We propose a model to explain the importance of this charge to gp41 structure and to HIV infection.

scholarly journals The crystal structure of Mycobacterium tuberculosis high-temperature requirement A protein reveals an autoregulatory mechanism

2018 ◽  
Vol 74 (12) ◽  
pp. 803-809
Author(s):  
Arvind Kumar Gupta ◽  
Debashree Behera ◽  
Balasubramanian Gopal
Keyword(s):  
Crystal Structure ◽  
Mycobacterium Tuberculosis ◽  
High Temperature ◽  
Catalytic Domain ◽  
Pdz Domain ◽  
Regulatory Pathways ◽  
Inactive Conformation ◽  
Temperature Requirement ◽  
Autoregulatory Mechanism

The crystal structure of Mycobacterium tuberculosis high-temperature requirement A (HtrA) protein was determined at 1.83 Å resolution. This membrane-associated protease is essential for the survival of M. tuberculosis. The crystal structure reveals that interactions between the PDZ domain and the catalytic domain in HtrA lead to an inactive conformation. This finding is consistent with its proposed role as a regulatory protease that is conditionally activated upon appropriate environmental triggers. The structure provides a basis for directed studies to evaluate the role of this essential protein and the regulatory pathways that are influenced by this protease.

Altering the Receptor−Effector Ratio by Transgenic Overexpression of Type V Adenylyl Cyclase:  Enhanced Basal Catalytic Activity and Function without Increased Cardiomyocyte β-Adrenergic Signalling†

Biochemistry ◽  
1999 ◽  
Vol 38 (50) ◽  
pp. 16706-16713 ◽  
Author(s):  
Nicole M. Tepe ◽  
John N. Lorenz ◽  
Atsuko Yatani ◽  
Rajesh Dash ◽  
Evangelia G. Kranias ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Adenylyl Cyclase ◽  
Type V ◽  
And Function

Establishing the role of PLVAP in protein-losing enteropathy: a homozygous missense variant leads to an attenuated phenotype

2018 ◽  
Vol 55 (11) ◽  
pp. 779-784 ◽  
Author(s):  
Alina Kurolap ◽  
Orly Eshach-Adiv ◽  
Claudia Gonzaga-Jauregui ◽  
Katya Dolnikov ◽  
Adi Mory ◽  
...  
Keyword(s):  
Barrier Function ◽  
Protein Function ◽  
Transmembrane Domain ◽  
Autosomal Recessive Inheritance ◽  
Missense Variant ◽  
Protein Loss ◽  
Protein Losing Enteropathy ◽  
Family Based ◽  
And Function

BackgroundIntestinal integrity is essential for proper nutrient absorption and tissue homeostasis, with damage leading to enteric protein loss, that is, protein-losing enteropathy (PLE). Recently, homozygous nonsense variants in the plasmalemma vesicle-associated protein gene (PLVAP) were reported in two patients with severe congenital PLE. PLVAP is the building block of endothelial cell (EC) fenestral diaphragms; its importance in barrier function is supported by mouse models of Plvap deficiency.ObjectiveTo genetically diagnose two first-degree cousins once removed, who presented with PLE at ages 22 and 2.5 years.MethodsFamily-based whole exome sequencing was performed based on an autosomal recessive inheritance model. In silico analyses were used to predict variant impact on protein structure and function.ResultsWe identified a rare homozygous variant (NM_031310.2:c.101T>C;p.Leu34Pro) in PLVAP, which co-segregated with the disease. Leu34 is predicted to be located in a highly conserved, hydrophobic, α-helical region within the protein’s transmembrane domain, suggesting Leu34Pro is likely to disrupt protein function and/or structure. Electron microscopy and PLVAP immunohistochemistry demonstrated apparently normal diaphragm morphology, predicted to be functionally affected.ConclusionsBiallelic missense variants in PLVAP can cause an attenuated form of the PLE and hypertriglyceridaemia syndrome. Our findings support the role of PLVAP in the pathophysiology of PLE, expand the phenotypic and mutation spectrums and underscore PLVAP’s importance in EC barrier function in the gut.

scholarly journals The critical role of Krüppel-like factors in kidney disease

2017 ◽  
Vol 312 (2) ◽  
pp. F259-F265 ◽  
Author(s):  
Sandeep K. Mallipattu ◽  
Chelsea C. Estrada ◽  
John C. He
Keyword(s):  
Current Knowledge ◽  
Critical Role ◽  
Vital Role ◽  
Glomerular Filtration Barrier ◽  
Kidney Fibrosis ◽  
Physiological Processes ◽  
Filtration Barrier ◽  
And Function ◽  
Mammalian Embryonic Development

Krüppel-like factors (KLFs) are a family of zinc-finger transcription factors critical to mammalian embryonic development, regeneration, and human disease. There is emerging evidence that KLFs play a vital role in key physiological processes in the kidney, ranging from maintenance of glomerular filtration barrier to tubulointerstitial inflammation to progression of kidney fibrosis. Seventeen members of the KLF family have been identified, and several have been well characterized in the kidney. Although they may share some overlap in their downstream targets, their structure and function remain distinct. This review highlights our current knowledge of KLFs in the kidney, which includes their pattern of expression and their function in regulating key biological processes. We will also critically examine the currently available literature on KLFs in the kidney and offer some key areas in need of further investigation.

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