TY  - JOUR
A1  - Floss, Doreen M.
A1  - Klöcker, Tobias
A1  - Schröder, Jutta
A1  - Lamertz, Larissa
A1  - Mrotzek, Simone
A1  - Strobl, Birgit
A1  - Hermanns, Heike
A1  - Scheller, Jürgen
T1  - Defining the functional binding sites of interleukin 12 receptor beta 1 and interleukin 23 receptor to Janus kinases
JF  - Molecular Biology of the Cell
N2  - The interleukin (IL)-12-type cytokines IL-12 and IL-23 are involved in T-helper (Th) 1 and Th17 immunity, respectively. They share the IL-12 receptor beta 1 (IL-12R beta 1) as one component of their receptor signaling complexes, with IL-12R beta 2 as second receptor for IL-12 and IL-23R for IL-23 signal transduction. Stimulation with IL-12 and IL-23 results in activation of receptor-associated Janus kinases (Jak) and phosphorylation of STAT proteins in target cells. The Janus kinase tyrosine kinase (Tyk) 2 associates with IL-12R beta 1, whereas Jak2 binds to IL-23R and also to IL-12R beta 2. Receptor association of Jak2 is mediated by Box1 and Box2 motifs located within the intracellular domain of the receptor chains. Here we define the Box1 and Box2 motifs in IL-12R beta 1 and an unusual Jak2-binding site in IL-23R by the use of deletion and site-directed mutagenesis. Our data show that nonfunctional box motifs abolish IL-12- and IL-23-induced STAT3 phosphorylation and cytokine-dependent proliferation of Ba/F3 cells. Coimmunoprecipitation of Tyk2 by IL-12R beta 1 and Jak2 by IL-23R supported these findings. In addition, our data demonstrate that association of Jak2 with IL-23R is mandatory for IL-12 and/or IL-23 signaling, whereas Tyk2 seems to be dispensable.
KW  - Tyrosine phosphorylation
KW  - Cytokine receptors
KW  - Intracellular domain
KW  - IL-12 family
KW  - Responses
KW  - Signal transduction
KW  - T-cells
KW  - STAT3 activation
KW  - Jak kinases
KW  - Inflammation
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188104
VL  - 27
IS  - 14
ER  - 
TY  - JOUR
A1  - Dietz, Mariana S.
A1  - Hasse, Daniel
A1  - Ferraris, Davide M.
A1  - Göhler, Antonia
A1  - Niemann, Hartmut H.
A1  - Heilemann, Mike
T1  - Single-molecule photobleaching reveals increased MET receptor dimerization upon ligand binding in intact cells
JF  - BMC Biophysics
N2  - Background: The human receptor tyrosine kinase MET and its ligand hepatocyte growth factor/scatter factor are essential during embryonic development and play an important role during cancer metastasis and tissue regeneration. In addition, it was found that MET is also relevant for infectious diseases and is the target of different bacteria, amongst them Listeria monocytogenes that induces bacterial uptake through the surface protein internalin B. Binding of ligand to the MET receptor is proposed to lead to receptor dimerization. However, it is also discussed whether preformed MET dimers exist on the cell membrane. 
Results: To address these issues we used single-molecule fluorescence microscopy techniques. Our photobleaching experiments show that MET exists in dimers on the membrane of cells in the absence of ligand and that the proportion of MET dimers increases significantly upon ligand binding. 
Conclusions: Our results indicate that partially preformed MET dimers may play a role in ligand binding or MET signaling. The addition of the bacterial ligand internalin B leads to an increase of MET dimers which is in agreement with the model of ligand-induced dimerization of receptor tyrosine kinases.
KW  - single-molecule photobleaching
KW  - fluorescence correlation spectroscopy
KW  - fluorescence
KW  - EGF receptor
KW  - rat hepatocytes
KW  - structural insights
KW  - Scatter factor
KW  - SEMA domain
KW  - hepatocyte-growth-factor
KW  - invasion protein-INLB
KW  - listeria-monocytogenes
KW  - tyrosine kinase
KW  - living cells
KW  - dimerization
KW  - MET receptor
KW  - Signal transduction
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121835
SN  - 2046-1682
VL  - 6
IS  - 6
ER  -