scholarly journals Betaglycan can act as a dual modulator of TGF-beta access to signaling receptors: mapping of ligand binding and GAG attachment sites

1994 ◽  
Vol 124 (4) ◽  
pp. 557-568 ◽  
Author(s):  
F López-Casillas ◽  
HM Payne ◽  
JL Andres ◽  
J Massagué
Keyword(s):  
Potent Inhibitor ◽  
Membrane Receptors ◽  
Deletion Mutants ◽  
Tgf Beta ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Terminal Domain ◽  
Extracellular Region ◽  
Attachment Sites ◽  
Signaling Receptors

Betaglycan, also known as the TGF-beta type III receptor, is a membrane-anchored proteoglycan that presents TGF-beta to the type II signaling receptor, a transmembrane serine/threonine kinase. The betaglycan extracellular region, which can be shed by cells into the medium, contains a NH2-terminal domain related to endoglin and a COOH-terminal domain related to uromodulin, sperm receptors Zp2 and 3, and pancreatic secretory granule GP-2 protein. We identified residues Ser535 and Ser546 in the uromodulin-related region as the glycosaminoglycan (GAG) attachment sites. Their mutation to alanine prevents GAG attachment but does not interfere with betaglycan stability or ability to bind and present TGF-beta to receptor II. Using a panel of deletion mutants, we found that TGF-beta binds to the NH2-terminal endoglin-related region of betaglycan. The remainder of the extracellular domain and the cytoplasmic domain are not required for presentation of TGF-beta to receptor II; however, membrane anchorage is required. Soluble betaglycan can bind TGF-beta but does not enhance binding to membrane receptors. In fact, recombinant soluble betaglycan acts as potent inhibitor of TGF-beta binding to membrane receptors and blocks TGF-beta action, this effect being particularly pronounced with the TGF-beta 2 isoform. The results suggest that release of betaglycan into the medium converts this enhancer of TGF-beta action into a TGF-beta antagonist.

X-ray structural studies of the entire extracellular region of the serine/threonine kinase PrkC from Staphylococcus aureus

2011 ◽  
Vol 435 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Alessia Ruggiero ◽  
Flavia Squeglia ◽  
Daniela Marasco ◽  
Roberta Marchetti ◽  
Antonio Molinaro ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Serine Threonine Kinase ◽  
X Ray ◽  
Threonine Kinase ◽  
Extracellular Milieu ◽  
Cellular Processes ◽  
Extracellular Region ◽  
High Concentrations ◽  
Growing Conditions ◽  
Adhesive Proteins

Bacterial serine/threonine kinases modulate a wide number of cellular processes. The serine/threonine kinase PrkC from the human pathogen Staphylococcus aureus was also shown to induce germination of Bacillus subtilis spores, in response to cell wall muropeptides. The presence of muropeptides in the bacterial extracellular milieu is a strong signal that the growing conditions are promising. In the present paper, we report the X-ray structure of the entire extracellular region of PrkC from S. aureus. This structure reveals that the extracellular region of PrkC, EC-PrkC, is a linear modular structure composed of three PASTA (penicillin binding-associated and serine/threonine kinase-associated) domains and an unpredicted C-terminal domain, which presents the typical features of adhesive proteins. Using several solution techniques, we also found that EC-PrkC shows no tendency to dimerize even in the presence of high concentrations of muropeptides. X-ray structural results obtained in the present study provide molecular clues into the mechanism of muropeptide-induced PrkC activation.

Mothers against dpp participates in a DDP/TGF-beta responsive serine-threonine kinase signal transduction cascade

Development ◽  
1997 ◽  
Vol 124 (16) ◽  
pp. 3167-3176 ◽  
Author(s):  
S.J. Newfeld ◽  
A. Mehra ◽  
M.A. Singer ◽  
J.L. Wrana ◽  
L. Attisano ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Nuclear Accumulation ◽  
Target Cells ◽  
Type I ◽  
Dependent Manner ◽  
Tgf Beta ◽  
Serine Threonine Kinase ◽  
Drosophila Cell ◽  
Threonine Kinase ◽  
Signal Transduction Cascade

Mothers against dpp (Mad) is the prototype of a family of genes required for signaling by TGF-beta related ligands. In Drosophila, Mad is specifically required in cells responding to Decapentaplegic (DPP) signals. We further specify the role of Mad in DPP-mediated signaling by utilizing tkvQ199D, an activated form of the DPP type I receptor serine-threonine kinase thick veins (tkv). In the embryonic midgut, tkvQ199D mimics DPP-mediated inductive interactions. Homozygous Mad mutations block signaling by tkvQ199D. Appropriate responses to signaling by tkvQ199D are restored by expression of MAD protein in DPP-target cells. Endogenous MAD is phosphorylated in a ligand-dependent manner in Drosophila cell culture. DPP overexpression in the embryonic midgut induces MAD nuclear accumulation; after withdrawal of the overexpressed DPP signal, MAD is detected only in the cytoplasm. However, in three different tissues and developmental stages actively responding to endogenous DPP, MAD protein is detected in the cytoplasm but not in the nucleus. From these observations, we discuss possible roles for MAD in a DPP-dependent serine-threonine kinase signal transduction cascade integral to the proper interpretation of DPP signals.

scholarly journals The conserved Pkh–Ypk kinase cascade is required for endocytosis in yeast

2002 ◽  
Vol 156 (2) ◽  
pp. 241-248 ◽  
Author(s):  
Amy K.A. deHart ◽  
Joshua D. Schnell ◽  
Damian A. Allen ◽  
Linda Hicke
Keyword(s):  
Fluid Phase ◽  
Receptor Internalization ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Extracellular Signals ◽  
Fluid Phase Endocytosis ◽  
Endocytic Machinery ◽  
Kinase Cascade ◽  
Signaling Receptors ◽  
Mutant Cells

Internalization of activated signaling receptors by endocytosis is one way cells downregulate extracellular signals. Like many signaling receptors, the yeast α-factor pheromone receptor is downregulated by hyperphosphorylation, ubiquitination, and subsequent internalization and degradation in the lysosome-like vacuole. In a screen to detect proteins involved in ubiquitin-dependent receptor internalization, we identified the sphingoid base–regulated serine–threonine kinase Ypk1. Ypk1 is a homologue of the mammalian serum– and glucocorticoid-induced kinase, SGK, which can substitute for Ypk1 function in yeast. The kinase activity of Ypk1 is required for receptor endocytosis because mutations in two residues important for its catalytic activity cause a severe defect in α-factor internalization. Ypk1 is required for both receptor-mediated and fluid-phase endocytosis, and is not necessary for receptor phosphorylation or ubiquitination. Ypk1 itself is phosphorylated by Pkh kinases, homologues of mammalian PDK1. The threonine in Ypk1 that is phosphorylated by Pkh1 is required for efficient endocytosis, and pkh mutant cells are defective in α-factor internalization and fluid-phase endocytosis. These observations demonstrate that Ypk1 acts downstream of the Pkh kinases to control endocytosis by phosphorylating components of the endocytic machinery.

An activated form of type I serine/threonine kinase receptor TARAM-A reveals a specific signalling pathway involved in fish head organiser formation

Development ◽  
1996 ◽  
Vol 122 (12) ◽  
pp. 3735-3743 ◽  
Author(s):  
A. Renucci ◽  
V. Lemarchandel ◽  
F. Rosa
Keyword(s):  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Axis Formation ◽  
Mesoderm Induction ◽  
Type I ◽  
Tgf Beta ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Anterior Dorsal ◽  
Dorsal Mesoderm

The role of Transforming Growth Factor beta (TGF-beta)-related molecules in axis formation and mesoderm patterning in vertebrates has been extensively documented, but the identity and mechanisms of action of the endogenous molecules remained uncertain. In this study, we isolate a novel serine/threonine kinase type I receptor, TARAM-A, expressed during early zebrafish embryogenesis first ubiquitously and then restricted to dorsal mesoderm during gastrulation. A constitutive form of the receptor is able to induce the most anterior dorsal mesoderm rapidly and to confer an anterior organizing activity. By contrast, the wild-type form is only able to induce a local expansion of the dorsal mesoderm. Thus an activated form of TARAM-A is sufficient to induce dorsoanterior structures and TARAM-A may be activated by dorsally localized signals. Our data suggest the existence in fish of a specific TGF-beta-related pathway for anterior dorsal mesoderm induction, possibly mediated by TARAM-A and activated at the late blastula stage by localized dorsal determinant.

The Drosophila saxophone gene: a serine-threonine kinase receptor of the TGF-beta superfamily

Science ◽  
1994 ◽  
Vol 263 (5154) ◽  
pp. 1756-1759 ◽  
Author(s):  
T Xie ◽  
A. Finelli ◽  
R. Padgett
Keyword(s):  
Tgf Beta ◽  
Serine Threonine Kinase ◽  
Threonine Kinase

scholarly journals A novel member of the transmembrane serine/threonine kinase receptor family is specifically expressed in the gonads and in mesenchymal cells adjacent to the mullerian duct

Development ◽  
1994 ◽  
Vol 120 (1) ◽  
pp. 189-197 ◽  
Author(s):  
W.M. Baarends ◽  
M.J. van Helmond ◽  
M. Post ◽  
P.J. van der Schoot ◽  
J.W. Hoogerbrugge ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Mesenchymal Cells ◽  
Type I ◽  
Mullerian Duct ◽  
Tgf Beta ◽  
Serine Threonine Kinase ◽  
Rnase Protection ◽  
Müllerian Duct ◽  
Threonine Kinase ◽  
Mullerian Ducts

The activin and TGF-beta type II receptors are members of a separate subfamily of transmembrane receptors with intrinsic protein kinase activity, which also includes the recently cloned TGF-beta type I receptor. We have isolated and characterized a cDNA clone (C14) encoding a new member of this subfamily. The domain structure of the C14-encoded protein corresponds with the structure of the other known transmembrane serine/threonine kinase receptors. It also contains the two inserts in the kinase domain that are characteristic for this subfamily. Using in situ hybridization, C14 mRNA was detected in the mesenchymal cells located adjacent to the mullerian ducts of males and females at day 15 (E15) of embryonic development. Marked C14 mRNA expression was also detected in the female gonads. In female E16 embryos, the C14 mRNA expression pattern remained similar to that in E15 embryos. However, in male E16 embryos C14 mRNA was detected in a circular area that includes the degenerating mullerian duct. The expression of C14 mRNA was also studied using RNase protection assays. At E15 and E16, C14 mRNA is expressed in the female as well as in the male urogenital ridge. However, at E19, a high C14 mRNA level in the female urogenital ridge contrasts with a lack of C14 mRNA in the male urogenital ridge. This correlates with the almost complete degeneration of the mullerian ducts in male embryos at E19. C14 mRNA expression was also detected in embryonic testes at E15, E16 and E19 using RNase protection assays, but at much lower levels than those found in the developing ovaries.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Functional Domains of Fused, a Serine-Threonine Kinase Required for Signaling in Drosophila

Genetics ◽  
1996 ◽  
Vol 142 (4) ◽  
pp. 1181-1198
Author(s):  
Pascal Thérond ◽  
Georges Alves ◽  
Bernadette Limbourg-Bouchon ◽  
Hervé Tricoire ◽  
Elizabeth Guillemet ◽  
...  
Keyword(s):  
Catalytic Domain ◽  
Kinase Domain ◽  
In Vitro Mutagenesis ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Terminal Domain ◽  
Segment Polarity ◽  
Protein Functions

Abstract fused (fu) is a segment-polarity gene encoding a putative serine-threonine kinase. In a wild-type context, all fu mutations display the same set of phenotypes. Nevertheless, mutations of the Suppressor of fused [Su(fu)] gene define three classes of alleles (fu0, fuI, fuII). Here, we report the molecular analysis of known fu mutations and the generation of new alleles by in vitro mutagenesis. We show that the Fused (Fu) protein functions in vivo as a kinase. The N-terminal kinase and the extreme C-terminal domains are necessary for Fu+ activity while a central region appears to be dispensable. We observe a striking correlation between the molecular lesions of fu mutations and the phenotype displayed in their interaction with Su(fu). Indeed, fuI alleles which are suppressed by Su(fu) mutations are defined by inframe alterations of the N-terminal catalytic domain whereas the C-terminal domain is missing or altered in all fuII alleles. An unregulated FuII protein, which can be limited to the 80 N-terminal amino acids of the kinase domain, would be responsible for the neomorphic costal-2 phenotype displayed by the fuII-Su(fu) interaction. We propose that the Fu C-terminal domain can differentially regulate the Fu catalytic domain according to cell position in the parasegment.

Abstract 15537: E2F1 Suppresses Fibrosis Through Serine-threonine Kinase Receptor Associated Protein (Strap)

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Dauren Biyashev ◽  
Chan Boriboun ◽  
Junlan Zhou ◽  
Gangjian Qin
Keyword(s):  
Signaling Pathway ◽  
Cancer Biology ◽  
Molecular Mechanisms ◽  
Cell Cycle Control ◽  
Tgf Beta ◽  
Serine Threonine Kinase ◽  
Receptor Associated Protein ◽  
Threonine Kinase ◽  
Proteomics Approach ◽  
Smad3 Protein

Background: E2F1 is best studied in cell-cycle control and cancer biology. Recently, we have disclosed a novel function of E2F1 that suppresses TGF-beta signaling pathway; however the underlying molecular mechanisms and physiological significance of this regulation remains unknown. Methods and Results: In a proteomics approach, Flag-tagged Smad3 protein was overexpressed in the embryonic fibroblasts (MEF) isolated from wild-type (WT) and E2F1-null (E2F1-KO) mice, and the Smad3-interacting proteins were isolated by co-immunoprecipitation and identified by mass spectrometry. Notably, the serine-threonine kinase receptor-associated protein (Strap) was found associated with Smad3 in WT MEFs, but not in E2F1-KO MEFs. This is important because Strap has been shown as inhibitor of canonical TGF-beta signaling pathway by interacting with both TGF-beta receptor I and Smad7 to interfere with Smad2/3 activation. When analyzed by Western blotting, we found that the expression of Strap was significantly higher in WT MEFs than in E2F1-KO MEFs, and similar results were obtained in the cardiac and lung tissues of WT and E2F1-KO mice. Remarkably, both bleomycin and Ang II treatments resulted in a significantly greater degree of lung fibrosis in E2F1-KO mice than in WT mice. Conclusion: Our results suggest that E2F1 suppresses tissue fibrosis through Strap expression and Strap-mediated repression of canonical TGF-beta signaling pathway.

DdNek2, the first non-vertebrate homologue of human Nek2, is involved in the formation of microtubule-organizing centers

2002 ◽  
Vol 115 (9) ◽  
pp. 1919-1929
Author(s):  
Ralph Gräf
Keyword(s):  
Catalytic Activity ◽  
Leucine Zipper ◽  
Catalytic Domain ◽  
Amino Acid Identity ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Microtubule Organizing Centers ◽  
Terminal Domain ◽  
C Terminus ◽  
Early Mitosis

Dictyostelium Nek2 (DdNek2) is the first structural and functional non-vertebrate homologue of human Nek2, a NIMA-related serine/threonine kinase required for centrosome splitting in early mitosis. DdNek2 shares 43% overall amino-acid identity with its human counterpart and 54% identity within the catalytic domain. Both proteins can be subdivided in an N-terminal catalytic domain, a leucine zipper and a C-terminal domain. Kinase assays with bacterially expressed DdNek2 and C-terminal deletion mutants revealed that catalytic activity requires the presence of the leucine zipper and that autophosphorylation occurs at the C-terminus. Microscopic analyses with DdNek2 antibodies and expression of a GFP-DdNek2 fusion protein in Dictyostelium showed that DdNek2 is a permanent centrosomal resident and suggested that it is a component of the centrosomal core. The GFP-DdNek2-overexpressing mutants frequently exhibit supernumerary microtubule-organizing centers (MTOCs). This phenotype did not require catalytic activity because it was also observed in cells expressing inactive GFP-K33R. However, it was shown to be caused by overexpression of the C-terminal domain since it also occurred in GFP-mutants expressing only the C-terminus or a leucine zipper/C-terminus construct but not in those mutants expressing only the catalytic domain or a catalytic domain/leucine zipper construct. These results suggest that DdNek2 is involved in the formation of MTOCs. Furthermore, the localization of the GFP-fusion proteins revealed two independent centrosomal targeting domains of DdNek2, one within the catalytic or leucine zipper domain and one in the C-terminal domain.

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