Strain-selective efficacy of sacubitril/valsartan on carotid fibrosis in response to injury in two inbred mouse strains.

Background And Purpose: Sacubitril/valsartan (Sac/val) is more effective than valsartan in lowering BP and mortality in patients with heart failure. Here, we proposed that Sac/val treatment would be more effective in preventing pathological vascular remodelling in 129X1/SvJ (129X1), than in C57BL/6J (B6) inbred mice.

Experimental Approach: Sac/val (60 mg·kg ·day ) and valsartan (27 mg·kg ·day ) were given as prophylactic or therapeutic treatments, to 129X1 or B6 mice with carotid artery ligation for 14 days.

Extracellular and Intracellular Cyclophilin A, Native and Post-Translationally Modified, Show Diverse and Specific Pathological Roles in Diseases.

CypA (cyclophilin A) is a ubiquitous and highly conserved protein with peptidyl prolyl isomerase activity. Because of its highly abundant level in the cytoplasm, most studies have focused on the roles of CypA as an intracellular protein. However, emerging evidence suggests an important role for extracellular CypA in the pathogenesis of several diseases through receptor (CD147 or other)-mediated autocrine and paracrine signaling pathways.

Sortilin facilitates VLDL-B100 secretion by insulin sensitive McArdle RH7777 cells.

Studies examining the relationship between cellular sortilin and VLDL-B100 secretion demonstrate inconsistent results. Current studies explore the possibility that discrepancies may be related to insulin sensitivity. McArdle RH7777 cells (McA cells) cultured under serum enriched conditions lose sensitivity to insulin.

G-protein-coupled receptor-2-interacting protein-1 is required for endothelial cell directional migration and tumor angiogenesis via cortactin-dependent lamellipodia formation.

Objective: Recent evidence suggests G-protein-coupled receptor-2-interacting protein-1 (GIT1) overexpression in several human metastatic tumors, including breast, lung, and prostate. Tumor metastasis is associated with an increase in angiogenesis. We have showed previously that GIT1 is required for postnatal angiogenesis during lung development.

Functional characterization of APOBEC-1 complementation factor phosphorylation sites.

ApoB mRNA editing involves site-specific deamination of cytidine 6666 producing an in-frame translation stop codon. Editing minimally requires APOBEC-1 and APOBEC-1 complementation factor (ACF). Metabolic stimulation of apoB mRNA editing in hepatocytes is associated with serine phosphorylation of ACF localized to editing competent, nuclear 27S editosomes.

APOBEC-1 and AID are nucleo-cytoplasmic trafficking proteins but APOBEC3G cannot traffic.

Human APOBEC3G (hA3G) is a member of the APOBEC-1 related protein (ARP) family of cytidine deaminases. hA3G functions as a natural defense against endogenous retrotransposons and a multitude of retroviruses, most notably human immunodeficiency virus type 1 (HIV-1). Nothing is known about the cellular function of hA3G, however, upon HIV-1 infection hA3G functions as an antiviral factor by mutating viral single-stranded DNA during reverse transcription.

Metabolic regulation of apoB mRNA editing is associated with phosphorylation of APOBEC-1 complementation factor.

Apolipoprotein B (apoB) mRNA editing is a nuclear event that minimally requires the RNA substrate, APOBEC-1 and APOBEC-1 Complementation Factor (ACF). The co-localization of these macro-molecules within the nucleus and the modulation of hepatic apoB mRNA editing activity have been described following a variety of metabolic perturbations, but the mechanism that regulates editosome assembly is unknown. APOBEC-1 was effectively co-immunoprecipitated with ACF from nuclear, but not cytoplasmic extracts.

Structural phylogenetic analysis of activation-induced deaminase function.

In mammals, activation-induced deaminase (AID) initiates somatic hypermutation (SHM) and class switch recombination (CSR) of Ig genes. SHM and CSR activities require separate regions within AID. A chromosome region maintenance 1 (CRM1)-dependent nuclear export signal (NES) at the AID C terminus is necessary for CSR, and has been suggested to associate with CSR-specific cofactors.

Hepatic very-low-density lipoprotein and apolipoprotein B production are increased following in vivo induction of betaine-homocysteine S-methyltransferase.

We have previously reported a positive correlation between the expression of BHMT (betaine-homocysteine S-methyltransferase) and ApoB (apolipoprotein B) in rat hepatoma McA (McArdle RH-7777) cells [Sowden, Collins, Smith, Garrow, Sparks and Sparks (1999) Biochem. J. 341, 639-645].

The structure of a yeast RNA-editing deaminase provides insight into the fold and function of activation-induced deaminase and APOBEC-1.

Activation-induced deaminase (AID) uses base deamination for class-switch recombination and somatic hypermutation and is related to the mammalian RNA-editing enzyme apolipoprotein B editing catalytic subunit 1 (APOBEC-1). CDD1 is a yeast ortholog of APOBEC-1 that exhibits cytidine deaminase and RNA-editing activity. Here, we present the crystal structure of CDD1 at 2.

Activation induced deaminase: the importance of being specific.

Activation-induced deaminase (AID) is required for class switch recombination and somatic hypermutation in immunoglobulin genes. Although the preponderance of evidence suggests that AID functions by deaminating deoxycytidine in DNA, the question remains whether it can also deaminate cytidine in mRNA, as originally proposed based on its homology to RNA-editing enzymes. Recently, the biological relevance of assaying mammalian enzymes for DNA deaminase activity using Escherichia coli DNA as a reporter has been questioned, representing another round in the ongoing debate.

Identification of novel alternative splice variants of APOBEC-1 complementation factor with different capacities to support apolipoprotein B mRNA editing.

Two novel mRNA transcripts have been identified that result from species- and tissue-specific, alternative polyadenylation and splicing of the pre-mRNA encoding the apolipoprotein B (apoB) editing catalytic subunit 1 (APOBEC-1) complementation factor (ACF) family of related proteins. The alternatively processed mRNAs encode 43- and 45-kDa proteins that are components of the previously identified p44 cluster of apoB RNA binding, editosomal proteins. Recombinant ACF45 displaced ACF64 and ACF43 in mooring sequence RNA binding but did not demonstrate strong binding to APOBEC-1.

Inducible expression of catalytically active type 1 serine/threonine protein phosphatase in a human carcinoma cell line.

BACKGROUND: One of the major cellular serine/threonine protein phosphatases is protein phosphatase type 1 (PP1). Studies employing many eukaryotic systems all point to a crucial role for PP1 activity in controlling cell cycle progression. One physiological substrate for PP1 appears to be the product of the retinoblastoma susceptibility gene (pRB), a demonstrated tumor suppressor.

Messenger RNA editing in mammals: new members of the APOBEC family seeking roles in the family business.

Alteration of mRNA sequence through base modification mRNA editing frequently generates protein diversity. Several proteins have been identified as being similar to C-to-U mRNA editing enzymes based on their structural domains and the occurrence of a catalytic domain characteristic of cytidine deaminases. In light of the hypothesis that these proteins might represent novel mRNA editing systems that could affect proteome diversity, we consider their structure, expression and relevance to biomedically significant processes or pathologies.

Increasing the yield of soluble recombinant protein expressed in E. coli by induction during late log phase.

Recombinant mammalian proteins expressed in E. coli can be difficult to purify in high yield in a soluble and functional form. Various techniques have been described to prevent proteolysis of expressed proteins and/or their sequestering as insoluble aggregates within inclusion bodies.

The editosome for cytidine to uridine mRNA editing has a native complexity of 27S: identification of intracellular domains containing active and inactive editing factors.

Apolipoprotein B mRNA cytidine to uridine editing requires the assembly of a multiprotein editosome comprised minimally of the catalytic subunit, apolipoprotein B mRNA editing catalytic subunit 1 (APOBEC-1), and an RNA-binding protein, APOBEC-1 complementation factor (ACF). A rat homolog has been cloned with 93.5% identity to human ACF (huACF).

Two proteins essential for apolipoprotein B mRNA editing are expressed from a single gene through alternative splicing.

Apolipoprotein B (apoB) mRNA editing involves site-specific deamination of cytidine to form uridine, resulting in the production of an in-frame stop codon. Protein translated from edited mRNA is associated with a reduced risk of atherosclerosis, and hence the protein factors that regulate hepatic apoB mRNA editing are of interest. A human protein essential for apoB mRNA editing and an eight-amino acid-longer variant of no known function have been recently cloned.