| 2004 |
DRAK2 raises the threshold for T cell activation by negatively regulating signals through the TCR. Drak2-/- T cells showed enhanced sensitivity to TCR-mediated stimulation with a reduced requirement for costimulation, but no defects in apoptosis or negative selection. |
Genetic knockout mouse model (Drak2-/- mice), functional T cell assays |
Immunity |
High |
15589167
|
| 2003 |
The calcium-binding protein CHP (calcineurin homologous protein) inhibits DRAK2 kinase activity (approximately 85% inhibition of both autophosphorylation and phosphorylation of myosin light chain substrate) in a calcium-dependent manner, while the CHP-DRAK2 physical interaction itself is not calcium-dependent. |
In vitro kinase assay, protein interaction studies |
Journal of biochemistry |
Medium |
12966074
|
| 2006 |
Nuclear localization of DRAK2 is required for UV-induced apoptosis. DRAK2 accumulates in the nucleus following UV irradiation, and nuclear-targeted DRAK2 (NLS fusion) causes cell death, while cytoplasmic DRAK2 does not. siRNA knockdown of DRAK2 partially suppressed UV-induced apoptosis. |
GFP-fusion localization, NLS mutagenesis, siRNA knockdown, UV irradiation apoptosis assay |
Biological & pharmaceutical bulletin |
Medium |
16462023
|
| 2007 |
DRAK2 contains a functional nuclear localization signal (NLS); phosphorylation of Ser350 (flanking the NLS) by PKC-gamma drives cytoplasmic localization. PMA induced cytoplasmic accumulation via PKC-gamma-mediated Ser350 phosphorylation, and the Ser350Asp mutant failed to accumulate in the nucleus upon UV irradiation. |
GFP-fusion NLS mutagenesis, ectopic PKC-gamma expression, PMA stimulation, site-directed mutagenesis (S350D) |
Journal of biochemistry |
Medium |
18084041
|
| 2006 |
DRAK2 autophosphorylates at Ser12, and this autophosphorylation is induced by antigen receptor stimulation in T and B cells in a calcium-dependent manner (blocked by BAPTA-AM, promoted by thapsigargin). Ser12 phosphorylation is necessary for optimal suppression of T cell activation. |
Mass spectrometry identification of autophosphorylation site, phospho-specific antibody, calcium chelation/mobilization experiments |
The Journal of biological chemistry |
Medium |
17182616
|
| 2005 |
DRAK2 controls the threshold for calcium signaling during thymocyte selection; Drak2-deficient positively selected thymocytes displayed a reduced requirement for TCR cross-linking. DRAK2 expression in DP thymocytes is induced by TCR stimulation in a PKC- and MAP kinase-dependent manner. |
Drak2-/- mouse thymocyte functional assays, retroviral transduction, TCR stimulation assays |
International immunology |
Medium |
16172133
|
| 2006 |
Transgenic Drak2 overexpression leads to enhanced apoptosis of activated T cells in the presence of IL-2, with lower increases in anti-apoptotic factors (Bcl-2, Bcl-xL) during activation, resulting in reduced memory T cell numbers. |
Transgenic mouse model (human beta-actin promoter-driven Drak2), IL-2 apoptosis assays, immunophenotyping |
The Journal of biological chemistry |
Medium |
16517594
|
| 2008 |
In Drak2-/- mice, T cells require greater tonic signaling for maintenance during clonal expansion and are more sensitive to intrinsic (mitochondrial) apoptosis following stimulation, which is prevented by CD28 ligation, homeostatic cytokines, or enforced Bcl-xL expression. T cell-specific Bcl-xL expression restored susceptibility to EAE in Drak2-/- mice. |
Drak2-/- mice, Bcl-xL transgenic rescue, adoptive transfer, apoptosis assays |
Journal of immunology |
High |
19017949
|
| 2009 |
DRAK2 is upstream of p70S6 kinase (S6K) in beta cell apoptosis signaling; inducible NO synthase is upstream of DRAK2 and caspase-9 is downstream. Purified DRAK2 directly phosphorylates p70S6 kinase in an in vitro kinase assay. DRAK2 overexpression enhanced p70S6K phosphorylation in cells, and DRAK2 knockdown reduced it. |
In vitro kinase assay with purified proteins, siRNA knockdown, transgenic overexpression, epistasis analysis |
Journal of immunology |
Medium |
19342653
|
| 2009 |
DRAK2 participates in a negative feedback loop controlling TGF-β signaling: TGF-β1 stimulation induces DRAK2 expression and promotes endogenous interaction of DRAK2 with the type I TGF-β receptor (TβRI), thereby blocking R-Smads recruitment. DRAK2 depletion markedly augmented TGF-β1 responses. |
Co-immunoprecipitation of DRAK2 with TβRI, siRNA knockdown, TGF-β signaling reporter assays, tumor cell line functional studies |
Cell reports |
Medium |
23122956
|
| 2010 |
Protein kinase D (PKD) is an essential upstream activator of DRAK2 following TCR ligation, requiring Ca2+ influx through Orai1 (CRAC channels). PKD physically interacts with DRAK2, phosphorylates it, and a constitutively active PKD mutant promoted DRAK2 function while kinase-dead PKD or PKD knockdown blocked DRAK2 activation. Mitochondrial reactive oxygen species generation was necessary and sufficient for DRAK2 activation in response to Ca2+ influx. |
PKD inhibitor (Gö6976), kinase-dead and constitutively active PKD mutants, PKD knockdown, Co-IP of DRAK2-PKD interaction, Orai1-dependent calcium influx assays |
Journal of immunology |
High |
21148796
|
| 2013 |
The MYB oncogene transcriptionally represses DRAK2 expression by binding to a conserved element upstream of the DRAK2 transcription start site. MYB knockdown upregulates DRAK2, activates caspase-9, and promotes apoptosis; DRAK2 siRNA knockdown rescues cells from this apoptosis. |
siRNA knockdown of MYB and DRAK2, ChIP assay showing MYB binding to DRAK2 promoter, caspase-9 activity assay |
Leukemia research |
Medium |
23398943
|
| 2015 |
DRAK2 does NOT regulate TGF-β/Smad signaling in primary T cells. Smad2/Smad3 activation, TGF-β-mediated effects on naïve T cell proliferation, CD8+ T cell survival, Treg induction, and enhanced T cell death in Drak2-/- mice were all independent of TGF-β signaling. |
In vitro TGF-β signaling assays in wildtype vs Drak2-/- primary T cells, Smad phosphorylation assays, proliferation and survival assays |
PloS one |
Medium |
25951457
|
| 2020 |
X-ray crystallography of STK17B with inhibitor SGC-STK17B-1 (thieno[3,2-d]pyrimidine) revealed a unique P-loop conformation characterized by a salt bridge between R41 and the carboxylic acid of the inhibitor, explaining selectivity over closely related STK17A. The compound is an ATP-competitive inhibitor. |
X-ray crystallography, kinase selectivity profiling, molecular dynamics simulation |
Journal of medicinal chemistry |
High |
33215924
|
| 2021 |
DRAK2 directly binds the splicing factor SRSF6 and inhibits its phosphorylation by SRPK1, thereby regulating alternative splicing of mitochondrial function-related genes and driving NAFLD/NASH progression. Hepatic deletion of DRAK2 suppressed hepatic steatosis progression to NASH. |
Phosphoproteome and transcriptome analyses, Co-IP/pulldown identifying SRSF6 as direct DRAK2 binding partner, DRAK2 conditional liver knockout mice, RNA splicing analysis |
Cell metabolism |
High |
34614409
|
| 2021 |
STK17B is strongly expressed in cerebellar Purkinje cells and functions as a downstream effector of PKC. STK17B overexpression potentiates PKC-induced morphological changes in Purkinje cell dendritic trees; a phosphorylation-mimetic STK17B variant caused marked reduction in dendritic tree size; and STK17B inhibition partially rescued PKC activation-induced dendritic changes. |
Overexpression and pharmacological inhibition in primary Purkinje cell cultures, phospho-mimetic mutant (STK17B-S350D equivalent), morphological quantification |
The European journal of neuroscience |
Medium |
34536317
|
| 2023 |
DRAK2 regulates IL-2 signaling by inhibiting STAT5A phosphorylation, not by limiting TCR signaling as previously hypothesized. Enhanced sensitivity to IL-2 in Drak2-/- mice augments thymic regulatory T cell (Treg) development, and resistance to T1D requires Treg presence. |
Drak2-/- NOD mice, T cell-specific conditional approaches, adoptive transfer with/without Tregs, STAT5A phosphorylation assays, Treg development analysis |
Cell reports |
Medium |
36773294
|
| 2024 |
DRAK2 directly phosphorylates ULK1 at Ser56, leading to ULK1 ubiquitylation and suppression of autophagy. In pancreatic β cells, this DRAK2-ULK1 axis impairs mitochondrial function and insulin secretion upon lipotoxic stress. Conditional β cell-specific DRAK2 knockout preserved autophagy and mitochondrial function under high-fat diet. |
Phosphoproteome analysis of primary mouse islets, ULK1-S56A point mutant rescue, DRAK2 conditional KO mice, in vitro kinase assay (direct phosphorylation), autophagy and mitochondrial function assays |
Science translational medicine |
High |
38324636
|
| 2024 |
DRAK2 phosphorylates myosin light chain 2 (MLC2) in T cells. In the absence of DRAK2, polymerized actin is decreased, and myosin-dependent T cell functions including migration, TCR microcluster accumulation, and conjugation to antigen-presenting cells are impaired. |
Drak2-/- T cell functional assays, actin polymerization assay, phosphorylation analysis of MLC2, T cell-APC conjugation assay, TCR microcluster imaging |
Journal of cell science |
Medium |
39421891
|
| 2024 |
Pharmacological STK17B inhibitors identify Ser19 on myosin light chain 2 (MLC2) as a STK17B substrate by mass spectrometry-based phosphoproteomics. In mouse T cell activation assays, STK17B inhibitors enhanced IL-2 production and enhanced T cell priming (CD69, IL-2, IFN-γ upregulation) in vivo. |
MS-based phosphoproteomics with selective kinase inhibitors, flow cytometry pharmacodynamic assay, in vivo T cell activation assay |
Frontiers in immunology |
Medium |
39502695
|
| 2026 |
STK17B phosphorylates IREB2 at Ser157 and HSPB1 at Ser15, identified by proximity labeling combined with phosphoproteomic analysis. This modulates the balance between proferroptotic transferrin receptor and antiferroptotic ferritin heavy chain, suppressing ferroptosis in multiple myeloma cells. STK17B also indirectly maintains activating phosphorylation of STAT3. |
Proximity labeling (BioID or similar) combined with phosphoproteomics, site-specific phosphorylation validation, ferroptosis assays (labile iron pool, lipid peroxidation), xenograft mouse model, selective STK17B inhibitor |
Blood |
Medium |
40953235
|