Abstract 283: The Coupling of Tumor Endothelial Marker-8 and Capillary Morphogenesis Gene-2 Receptors to Contractile-Related Signaling Pathway in Cardiac Myocytes

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Damir Nizamutdinov ◽  
Honey B Golden ◽  
Hao Feng ◽  
Fnu Gerilechaogetu ◽  
Donald M Foster ◽  
...  
Keyword(s):  
Cardiac Myocytes ◽  
Anthrax Toxin ◽  
Neonatal Rat ◽  
Regulatory Pathways ◽  
Capillary Morphogenesis ◽  
Downstream Signaling ◽  
Signaling Mechanisms ◽  
Toxin Receptor ◽  
Tumor Endothelial Marker 8 ◽  
Endothelial Marker

Recent molecular and pharmacological studies performed on non-cardiac tissues suggest that tumor endothelial marker-8 (TEM-8), also known as anthrax toxin receptor 1 (ANTXR1) and capillary morphogenesis gene-2 (CMG-2), known as anthrax toxin receptor 2 (ANTXR2) regulate survival, proliferation, cell shape, as well as polarity, adhesion, migration and differentiation. However, downstream signaling mechanisms and function of these molecules have not been studied. Recent studies indicate that activation of protein kinase B (Akt) and c-Jun N-terminal kinases (JNK) have been associated with hypertrophic growth, as well as regulation of contractility in cardiac myocytes (CM). In this study we’ve investigated the role of ANTXR1 and ANTXR2 receptors in intracellular pathways of contractility regulation in neonatal rat ventricular myocytes (NRVM). Primary culture of NRVM was used to determine the effects of ANTXR1/ANTXR2 activation on Akt and JNK phosphorylation by Western blot analysis. Flow cytometry and immunostaining of alive CM were used to determine expression levels and distribution of anthrax receptors throughout the cells. Furin-activated form of anthrax protective antigen (PA 63 ) was used in order to selectively stimulate ANTXR1/ANTXR2 receptors and get understanding of downstream signaling mechanisms coupled to them. The treatments with angiotensin II, type1 receptor (AT 1 ) inhibitors were used in order to separate responses of distinct regulatory pathways of contractility. All treatments were done at variable time courses started in seconds and finished in half of hour to determine a sequence of phosphorylation reactions going from cellular membrane to deep inside of cell. As a result, abundant expression of both receptors was observed in cardiac myocytes. Activation of one phospho-site of focal adhesion kinase (FAK 861 ) was started in 15 sec with subsequent phosphorylation of JNK and Akt 473 in 5 and 10 minutes. Involvement of new molecules was observed in cascade chain reaction of contractility regulation. In conclusion, ANTXR1/ANTXR2 were demonstrated to couple to mechano-sensor molecules: FAK, Akt and JNK, as well as interact with the AT 1 receptors to mediate downstream signaling events responsible for regulation of contractility.

scholarly journals Anthrax Toxin Receptor 1/Tumor Endothelial Marker 8: Mutation of Conserved Inserted Domain Residues Overrides Cytosolic Control of Protective Antigen Binding

Biochemistry ◽  
2010 ◽  
Vol 49 (34) ◽  
pp. 7403-7410 ◽  
Author(s):  
Jordan D. Ramey ◽  
Valerie A. Villareal ◽  
Charles Ng ◽  
Sabrina C. Ward ◽  
Jian-Ping Xiong ◽  
...  
Keyword(s):  
Protective Antigen ◽  
Anthrax Toxin ◽  
Antigen Binding ◽  
Toxin Receptor ◽  
Tumor Endothelial Marker 8 ◽  
Endothelial Marker

The AMPK γ1 R70Q mutant regulates multiple metabolic and growth pathways in neonatal cardiac myocytes

2007 ◽  
Vol 293 (6) ◽  
pp. H3456-H3464 ◽  
Author(s):  
Karalyn D. Folmes ◽  
Lee A. Witters ◽  
Michael F. Allard ◽  
Martin E. Young ◽  
Jason R. B. Dyck
Keyword(s):  
Cardiac Hypertrophy ◽  
Cardiac Myocytes ◽  
Glycogen Synthase ◽  
Neonatal Rat ◽  
Mrna Levels ◽  
Glycogen Accumulation ◽  
Regulatory Pathways ◽  
Γ Subunit ◽  
Gsk 3Β ◽  
Glycogen Synthase Activity

Although mutations in the γ-subunit of AMP-activated protein kinase (AMPK) can result in excessive glycogen accumulation and cardiac hypertrophy, the mechanisms by which this occurs have not been well defined. Because >65% of cardiac AMPK activity is associated with the γ1-subunit of AMPK, we investigated the effects of expression of an AMPK-activating γ1-subunit mutant (γ1 R70Q) on regulatory pathways controlling glycogen accumulation and cardiac hypertrophy in neonatal rat cardiac myocytes. Whereas expression of γ1 R70Q displayed the expected increase in palmitate oxidation rates, rates of glycolysis were significantly depressed. In addition, glycogen synthase activity was increased in cardiac myocytes expressing γ1 R70Q, due to both increased expression and decreased phosphorylation of glycogen synthase. The inhibition of glycolysis and increased glycogen synthase activity were correlated with elevated glycogen levels in γ1 R70Q-expressing myocytes. In association with the reduced phosphorylation of glycogen synthase, glycogen synthase kinase (GSK)-3β protein and mRNA levels were profoundly decreased in the γ1 R70Q-expressing myocytes. Consistent with GSK-3β negatively regulating hypertrophy via inhibition of nuclear factor of activated T cells (NFAT), the dramatic downregulation of GSK-3β was associated with increased nuclear activity of NFAT. Together, these data provide important new information about the mechanisms by which a mutation in the γ-subunit of AMPK causes altered AMPK signaling and identify multiple pathways involved in regulating both cardiac myocyte metabolism and growth that may contribute to the development of the γ mutant-associated cardiomyopathy.

scholarly journals Human capillary morphogenesis protein 2 functions as an anthrax toxin receptor

2003 ◽  
Vol 100 (9) ◽  
pp. 5170-5174 ◽  
Author(s):  
H. M. Scobie ◽  
G. J. A. Rainey ◽  
K. A. Bradley ◽  
J. A. T. Young
Keyword(s):  
Anthrax Toxin ◽  
Capillary Morphogenesis ◽  
Toxin Receptor

scholarly journals A canstatin-derived peptide provides insight into the role of Capillary Morphogenesis Gene 2 in angiogenic regulation and matrix uptake

2019 ◽  
Author(s):  
Jordan G. Finnell ◽  
Tsz-Ming Tsang ◽  
Lorna Cryan ◽  
Samuel Garrard ◽  
Sai-Lun Lee ◽  
...  
Keyword(s):  
Metal Ion ◽  
Protective Antigen ◽  
Anthrax Toxin ◽  
Peptide Array ◽  
Peptide Fragments ◽  
Capillary Morphogenesis ◽  
Type Iv ◽  
Toxin Receptor ◽  
Affinity Peptide ◽  
Von Willebrand

AbstractCapillary Morphogenesis Gene 2 protein (CMG2) is a transmembrane, integrin-like receptor and the primary receptor for the anthrax toxin. In addition to its role as an anthrax toxin receptor, CMG2 has been repeatedly shown to play a role in angiogenic processes. However, the molecular mechanism mediating observed CMG2-related angiogenic effects has not been fully elucidated. Previous studies have found that CMG2 binds type IV collagen (Col-IV), a key component of the vascular basement membrane, as well as other ECM proteins. Currently, no link has been made between these CMG2-ECM interactions and angiogenesis; however, ECM fragments are known to play a role in regulating angiogenesis. Here, we further characterize the CMG2-Col-IV interaction and explore the effect of this interaction on angiogenesis. Using a peptide array, we observed that CMG2 preferentially binds peptide fragments of the NC1 (non-collagenous domain 1) domains of Col-IV. These domains are also known as the fragments arresten (from the α1 chain) and canstatin (from the α2 chain) and have documented antiangiogenic properties. A second peptide array was probed to map a putative binding epitope. A top hit from the initial array, a canstatin-derived peptide, binds to the CMG2 ligand-binding von Willebrand factor A (vWA) domain with sub-micromolar affinity (peptide S16, Kd = 400 ± 200 nM). This peptide competes with anthrax protective antigen (PA) for CMG2 binding, and does not bind CMG2 in the presence of EDTA. Together these data suggest that, like PA, S16 interacts with CMG2 at the metal-ion dependent adhesion site (MIDAS) of its vWA domain. We demonstrate that CMG2 specifically mediates endocytic uptake of S16, since CMG2-/- endothelial cells show markedly reduced S16 uptake, without reducing total endocytosis. Furthermore, we show that S16 reduces endothelial migration but not cell proliferation. Taken together, our data demonstrate that a Col IV-derived anti-angiogenic peptide acts via CMG2, suggesting a possible link between CMG2-Col IV interactions and angiogenesis.

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