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.

scholarly journals ZIP Kinase, a Novel Serine/Threonine Kinase Which Mediates Apoptosis

1998 ◽  
Vol 18 (3) ◽  
pp. 1642-1651 ◽  
Author(s):  
Taro Kawai ◽  
Makoto Matsumoto ◽  
Kiyoshi Takeda ◽  
Hideki Sanjo ◽  
Shizuo Akira
Keyword(s):  
Leucine Zipper ◽  
Catalytic Domain ◽  
Morphological Changes ◽  
Kinase Domain ◽  
Leucine Zippers ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
C Terminus ◽  
Death Associated Protein Kinase ◽  
Element Binding Protein

ABSTRACT We have identified a novel serine/threonine kinase, designated ZIP kinase, which mediates apoptosis. ZIP kinase contains a leucine zipper structure at its C terminus, in addition to a kinase domain at its N terminus. ZIP kinase physically binds to ATF4, a member of the activating transcription factor/cyclic AMP-responsive element-binding protein (ATF/CREB) family, through interaction between their leucine zippers. The leucine zipper domain is necessary for the homodimerization of ZIP kinase as well as for the activation of kinase. Immunostaining study showed that ZIP kinase localizes in the nuclei. Overexpression of intact ZIP kinase but not catalytically inactive kinase mutants led to the morphological changes of apoptosis in NIH 3T3 cells, suggesting that the cell death-inducing activity of ZIP kinase depends on its intrinsic kinase activity. Interestingly, the catalytic domain of ZIP kinase is closely related to that of death-associated protein kinase (DAP kinase), which is a mediator of apoptosis induced by gamma interferon. Therefore, both ZIP and DAP kinases represent a novel kinase family, which mediates apoptosis through their catalytic activities.

scholarly journals Plasma membrane-targeted ras GTPase-activating protein is a potent suppressor of p21ras function.

1993 ◽  
Vol 13 (4) ◽  
pp. 2420-2431 ◽  
Author(s):  
D C Huang ◽  
C J Marshall ◽  
J F Hancock
Keyword(s):  
Plasma Membrane ◽  
Catalytic Activity ◽  
Catalytic Domain ◽  
Cell Transformation ◽  
Negative Regulator ◽  
Membrane Localization ◽  
Plasma Membrane Localization ◽  
Terminal Domain ◽  
3T3 Fibroblasts ◽  
C Terminus

Although p21ras is localized to the plasma membrane, proteins it interacts with, such as the GTPase-activating proteins (GAPs) ras GAP and neurofibromin (NF1), are not, suggesting that one function of p21ras GTP may be to target such proteins to the plasma membrane. To investigate the effects of targeting ras GAP to the plasma membrane, ras C-terminal motifs sufficient for plasma membrane localization of p21ras were cloned onto the C terminus of ras GAP. Plasma membrane-targeted ras GAP is growth inhibitory to NIH 3T3 fibroblasts and COS cells. This growth inhibition correlates with GAP catalytic activity, since the plasma membrane-targeted C-terminal catalytic domain or the GAP-related domain of neurofibromin is inhibitory, whereas the similarly targeted N-terminal domain is not. Moreover, the inhibition is abrogated by the inactivating mutation L902I, which abolishes ras GAP catalytic activity. Coexpression of oncogenic mutant ras rescues cell viability, but the majority of rescued colonies are phenotypically untransformed. Furthermore, in focus assays, targeted ras GAP suppresses transformation by oncogenic mutant ras, and in reversion assays, targeted ras GAP can revert cells transformed by oncogenic mutant ras. Neither the targeted or nontargeted N-terminal domain nor the L902I mutant of ras GAP has any transforming activity. These data demonstrate that ras GAP can function as a negative regulator of ras and that plasma membrane localization potentiates this activity. However, if ras GAP is involved in the effector functions of p21ras, it can only be part of the effector complex for cell transformation.

Plasma membrane-targeted ras GTPase-activating protein is a potent suppressor of p21ras function

1993 ◽  
Vol 13 (4) ◽  
pp. 2420-2431
Author(s):  
D C Huang ◽  
C J Marshall ◽  
J F Hancock
Keyword(s):  
Plasma Membrane ◽  
Catalytic Activity ◽  
Catalytic Domain ◽  
Cell Transformation ◽  
Negative Regulator ◽  
Membrane Localization ◽  
Plasma Membrane Localization ◽  
Terminal Domain ◽  
3T3 Fibroblasts ◽  
C Terminus

Although p21ras is localized to the plasma membrane, proteins it interacts with, such as the GTPase-activating proteins (GAPs) ras GAP and neurofibromin (NF1), are not, suggesting that one function of p21ras GTP may be to target such proteins to the plasma membrane. To investigate the effects of targeting ras GAP to the plasma membrane, ras C-terminal motifs sufficient for plasma membrane localization of p21ras were cloned onto the C terminus of ras GAP. Plasma membrane-targeted ras GAP is growth inhibitory to NIH 3T3 fibroblasts and COS cells. This growth inhibition correlates with GAP catalytic activity, since the plasma membrane-targeted C-terminal catalytic domain or the GAP-related domain of neurofibromin is inhibitory, whereas the similarly targeted N-terminal domain is not. Moreover, the inhibition is abrogated by the inactivating mutation L902I, which abolishes ras GAP catalytic activity. Coexpression of oncogenic mutant ras rescues cell viability, but the majority of rescued colonies are phenotypically untransformed. Furthermore, in focus assays, targeted ras GAP suppresses transformation by oncogenic mutant ras, and in reversion assays, targeted ras GAP can revert cells transformed by oncogenic mutant ras. Neither the targeted or nontargeted N-terminal domain nor the L902I mutant of ras GAP has any transforming activity. These data demonstrate that ras GAP can function as a negative regulator of ras and that plasma membrane localization potentiates this activity. However, if ras GAP is involved in the effector functions of p21ras, it can only be part of the effector complex for cell transformation.

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.

Reversible ubiquitination regulates the Smad/TGF-β signalling pathway

2006 ◽  
Vol 34 (5) ◽  
pp. 761-763 ◽  
Author(s):  
S.J. Wicks ◽  
T. Grocott ◽  
K. Haros ◽  
M. Maillard ◽  
P. ten Dijke ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Type I ◽  
Serine Threonine Kinase ◽  
Full Spectrum ◽  
Threonine Kinase ◽  
Pathological Conditions ◽  
C Terminus ◽  
Β Receptor ◽  
Fine Tune

TGF-β (transforming growth factor-β) signals through serine/threonine kinase receptors and intracellular Smad transcription factors. An important regulatory step involves specific ubiquitination by Smurfs (Smad–ubiquitin regulatory factors), members of the HECT (homologous to E6-associated protein C-terminus) ubiquitin ligase family, which mediate the proteasomal degradation of Smads and/or receptors. Recently, we have defined a novel interaction between Smads and UCH37 (ubiquitin C-terminal hydrolase 37), a DUB (de-ubiquitinating enzyme) that could potentially counteract Smurf-mediated ubiquitination. We have demonstrated specific interactions between UCH37 and inhibitory Smad7, as well as weaker associations with Smad2 and Smad3. Importantly, Smad7 can act as an adaptor able to recruit UCH37 to the type I TGF-β receptor. Consequently, UCH37 dramatically up-regulates TGF-β-dependent gene expression by de-ubiquitinating and stabilizing the type I TGF-β receptor. Our findings suggest that competing effects of ubiquitin ligases and DUBs in complex with Smad7 can serve to fine-tune responses to TGF-βs under various physiological and pathological conditions. Studies are currently under way using activity-based HA (haemagglutinin)-tagged ubiquitin probes to identify the full spectrum of DUBs that impact on Smad/TGF-β signalling activity.

scholarly journals Crystal structure of microtubule affinity-regulating kinase 4 catalytic domain in complex with a pyrazolopyrimidine inhibitor

2016 ◽  
Vol 72 (2) ◽  
pp. 129-134 ◽  
Author(s):  
John S. Sack ◽  
Mian Gao ◽  
Susan E. Kiefer ◽  
Joseph E. Myers ◽  
John A. Newitt ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Catalytic Domain ◽  
Neurofibrillary Tangle ◽  
Binding Pocket ◽  
Atp Binding ◽  
Activation Loop ◽  
Serine Threonine Kinase ◽  
Atp Binding Site ◽  
Threonine Kinase ◽  
Catalytic Loop

Microtubule-associated protein/microtubule affinity-regulating kinase 4 (MARK4) is a serine/threonine kinase involved in the phosphorylation of MAP proteins that regulate microtubule dynamics. Abnormal activity of MARK4 has been proposed to contribute to neurofibrillary tangle formation in Alzheimer's disease. The crystal structure of the catalytic and ubiquitin-associated domains of MARK4 with a potent pyrazolopyrimidine inhibitor has been determined to 2.8 Å resolution with anRworkof 22.8%. The overall structure of MARK4 is similar to those of the other known MARK isoforms. The inhibitor is located in the ATP-binding site, with the pyrazolopyrimidine group interacting with the inter-lobe hinge region while the aminocyclohexane moiety interacts with the catalytic loop and the DFG motif, forcing the activation loop out of the ATP-binding pocket.

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 structures of the kinase domain and UBA domain of MPK38 suggest the activation mechanism for kinase activity

2014 ◽  
Vol 70 (2) ◽  
pp. 514-521 ◽  
Author(s):  
Yong-Soon Cho ◽  
Jiho Yoo ◽  
Soomin Park ◽  
Hyun-Soo Cho
Keyword(s):  
Drug Target ◽  
Leucine Zipper ◽  
Kinase Domain ◽  
Activation Mechanism ◽  
Activation Loop ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Extended Sequence ◽  
Uba Domain ◽  
Cleft Closure

Murine protein serine/threonine kinase 38 (MPK38) is the murine orthologue of human maternal embryonic leucine-zipper kinase (MELK), which belongs to the SNF1/AMPK family. MELK is considered to be a promising drug target for anticancer therapy because overexpression and hyperactivation of MELK is correlated with several human cancers. Activation of MPK38 requires the extended sequence (ExS) containing the ubiquitin-associated (UBA) linker and UBA domain and phosphorylation of the activation loop. However, the activation mechanism of MPK38 is unknown. This paper reports the crystal structure of MPK38 (T167E), which mimics a phosphorylated state of the activation loop, in complex with AMP-PNP. In the MPK38 structure, the UBA linker forces an inward movement of the αC helix. Phosphorylation of the activation loop then induces movement of the activation loop towards the C-lobe and results in interlobar cleft closure. These processes generate a fully active state of MPK38. This structure suggests that MPK38 has a similar molecular mechanism regulating activation as in other kinases of the SNF1/AMPK family.

scholarly journals Death-Associated Protein Kinase-Related Protein 1, a Novel Serine/Threonine Kinase Involved in Apoptosis

2000 ◽  
Vol 20 (3) ◽  
pp. 1044-1054 ◽  
Author(s):  
Boaz Inbal ◽  
Gidi Shani ◽  
Ofer Cohen ◽  
Joseph L. Kissil ◽  
Adi Kimchi
Keyword(s):  
Catalytic Domain ◽  
Function Analysis ◽  
Regulatory Region ◽  
Dominant Negative ◽  
Dependent Manner ◽  
Related Protein ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Functional Connections ◽  
Dap Kinase

ABSTRACT In this study we describe the identification and structure-function analysis of a novel death-associated protein (DAP) kinase-related protein, DRP-1. DRP-1 is a 42-kDa Ca2+/calmodulin (CaM)-regulated serine threonine kinase which shows high degree of homology to DAP kinase. The region of homology spans the catalytic domain and the CaM-regulatory region, whereas the remaining C-terminal part of the protein differs completely from DAP kinase and displays no homology to any known protein. The catalytic domain is also homologous to the recently identified ZIP kinase and to a lesser extent to the catalytic domains of DRAK1 and -2. Thus, DAP kinase DRP-1, ZIP kinase, and DRAK1/2 together form a novel subfamily of serine/threonine kinases. DRP-1 is localized to the cytoplasm, as shown by immunostaining and cellular fractionation assays. It binds to CaM, undergoes autophosphorylation, and phosphorylates an exogenous substrate, the myosin light chain, in a Ca2+/CaM-dependent manner. The truncated protein, deleted of the CaM-regulatory domain, was converted into a constitutively active kinase. Ectopically expressed DRP-1 induced apoptosis in various types of cells. Cell killing by DRP-1 was dependent on two features: the status of the catalytic activity, and the presence of the C-terminal 40 amino acids shown to be required for self-dimerization of the kinase. Interestingly, further deletion of the CaM-regulatory region could override the indispensable role of the C-terminal tail in apoptosis and generated a “superkiller” mutant. A dominant negative fragment of DAP kinase encompassing the death domain was found to block apoptosis induced by DRP-1. Conversely, a catalytically inactive mutant of DRP-1, which functioned in a dominant negative manner, was significantly less effective in blocking cell death induced by DAP kinase. Possible functional connections between DAP kinase and DRP-1 are discussed.

scholarly journals Crystal Structure of the Catalytic Domain of the PknB Serine/Threonine Kinase fromMycobacterium tuberculosis

2003 ◽  
Vol 278 (15) ◽  
pp. 13094-13100 ◽  
Author(s):  
Miguel Ortiz-Lombardı́a ◽  
Frédérique Pompeo ◽  
Brigitte Boitel ◽  
Pedro M. Alzari
Keyword(s):  
Crystal Structure ◽  
Catalytic Domain ◽  
Serine Threonine Kinase ◽  
Threonine Kinase
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