TY  - JOUR
A1  - Tilstam, Pathricia V.
A1  - Gijbels, Marion J.
A1  - Habbeddine, Mohamed
A1  - Cudejko, Celine
A1  - Asare, Yaw
A1  - Theelen, Wendy
A1  - Zhou, Baixue
A1  - Döring, Yvonne
A1  - Drechsler, Maik
A1  - Pawig, Lukas
A1  - Simsekyilmaz, Sakine
A1  - Koenen, Rory R.
A1  - de Winther, Menno P. J.
A1  - Lawrence, Toby
A1  - Bernhagen, Jürgen
A1  - Zernecke, Alma
A1  - Weber, Christian
A1  - Noels, Heidi
T1  - Bone Marrow-Specific Knock-In of a Non-Activatable Ikkα Kinase Mutant Influences Haematopoiesis but Not Atherosclerosis in Apoe-Deficient Mice
JF  - PLOS ONE
N2  - Background: The Ikkα kinase, a subunit of the NF-kappa B-activating IKK complex, has emerged as an important regulator of inflammatory gene expression. However, the role of Ikkα-mediated phosphorylation in haematopoiesis and atherogenesis remains unexplored. In this study, we investigated the effect of a bone marrow (BM)-specific activation-resistant Ikk alpha mutant knock-in on haematopoiesis and atherosclerosis in mice. 
Methods and Results: Apolipoprotein E (Apoe)-deficient mice were transplanted with BM carrying an activation-resistant Ikkα gene (Ikkα(AA/AA) Apoe(-/-)) or with Ikkα(+/+) Apoe(-/-) BM as control and were fed a high-cholesterol diet for 8 or 13 weeks. Interestingly, haematopoietic profiling by flow cytometry revealed a significant decrease in B-cells, regulatory T-cells and effector memory T-cells in Ikkα(AA/AA) Apoe(-/-) BM-chimeras, whereas the naive T-cell population was increased. Surprisingly, no differences were observed in the size, stage or cellular composition of atherosclerotic lesions in the aorta and aortic root of Ikkα(AA/AA) Apoe(-/-) vs Ikkα(+/+) Apoe(-/-) BM-transplanted mice, as shown by histological and immunofluorescent stainings. Necrotic core sizes, apoptosis, and intracellular lipid deposits in aortic root lesions were unaltered. In vitro, BM-derived macrophages from Ikkα(AA/AA) Apoe(-/-) vs Ikkα(+/+) Apoe(-/-) mice did not show significant differences in the uptake of oxidized low-density lipoproteins (oxLDL), and, with the exception of Il-12, the secretion of inflammatory proteins in conditions of Tnf-α or oxLDL stimulation was not significantly altered. Furthermore, serum levels of inflammatory proteins as measured with a cytokine bead array were comparable. 
Conclusion: Our data reveal an important and previously unrecognized role of haematopoietic Ikkα kinase activation in the homeostasis of B-cells and regulatory T-cells. However, transplantation of Ikkα AA mutant BM did not affect atherosclerosis in Apoe(-/-) mice. This suggests that the diverse functions of Ikkα in haematopoietic cells may counterbalance each other or may not be strong enough to influence atherogenesis, and reveals that targeting haematopoietic Ikkα kinase activity alone does not represent a therapeutic approach.
KW  - NF-KAPPA-B
KW  - regulatory T cells
KW  - indoleamine 2,3-dioxygenase
KW  - dendritic cells
KW  - gene expression
KW  - increases atherosclersosis
KW  - receptor
KW  - inhibition
KW  - pathway
KW  - beta
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117450
VL  - 9
IS  - 2
ER  - 
TY  - JOUR
A1  - Zhao, Bo
A1  - Zhang, Keya
A1  - Bhuripanyo, Karan
A1  - Choi, Chan Hee J.
A1  - Villhauer, Eric B.
A1  - Li, Heng
A1  - Zheng, Ning
A1  - Kiyokawa, Hiroaki
A1  - Schindelin, Hermann
A1  - Yin, Jun
T1  - Profiling the Cross Reactivity of Ubiquitin with the Nedd8 Activating Enzyme by Phage Display
JF  - PLoS ONE
N2  - The C-terminal peptides of ubiquitin (UB) and UB-like proteins (UBLs) play a key role in their recognition by the specific activating enzymes (E1s) to launch their transfer through the respective enzymatic cascades thus modifying cellular proteins. UB and Nedd8, a UBL regulating the activity of cullin-RING UB ligases, only differ by one residue at their C-termini; yet each has its specific E1 for the activation reaction. It has been reported recently that UAE can cross react with Nedd8 to enable its passage through the UB transfer cascade for protein neddylation. To elucidate differences in UB recognition by UAE and NAE, we carried out phage selection of a UB library with randomized C-terminal sequences based on the catalytic formation of UB similar to NAE thioester conjugates. Our results confirmed the previous finding that residue 72 of UB plays a "gate-keeping" role in E1 selectivity. We also found that diverse sequences flanking residue 72 at the UB C-terminus can be accommodated by NAE for activation. Furthermore heptameric peptides derived from the C-terminal sequences of UB variants selected for NAE activation can function as mimics of Nedd8 to form thioester conjugates with NAE and the downstream E2 enzyme Ubc12 in the Nedd8 transfer cascade. Once the peptides are charged onto the cascade enzymes, the full-length Nedd8 protein is effectively blocked from passing through the cascade for the critical modification of cullin. We have thus identified a new class of inhibitors of protein neddylation based on the profiles of the UB C-terminal sequences recognized by NAE.
KW  - protein NEDD8
KW  - E1
KW  - system
KW  - conjugation
KW  - pathway
KW  - complex
KW  - ligases
KW  - purification
KW  - neddylation
KW  - expression
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128479
SN  - 1932-6203
VL  - 8
IS  - e70312
ER  -