DDR1 autophosphorylation is a result of aggregation into dense clusters

AbstractThe collagen receptor DDR1 is a receptor tyrosine kinase that promotes progression of a wide range of human disorders. Little is known about how ligand binding triggers DDR1 kinase activity. We previously reported that collagen induces DDR1 activation through lateral dimer association and phosphorylation between dimers, a process that requires specific transmembrane association. Here we demonstrate ligand-induced DDR1 clustering by widefield and super-resolution imaging and provide evidence for a mechanism whereby DDR1 kinase activity is determined by its molecular density. Ligand binding resulted in initial DDR1 reorganisation into morphologically distinct clusters with unphosphorylated DDR1. Further compaction over time led to clusters with highly aggregated and phosphorylated DDR1. Ligand-induced DDR1 clustering was abolished by transmembrane mutations but did not require kinase activity. Our results significantly advance our understanding of the molecular events underpinning ligand-induced DDR1 kinase activity and provide an explanation for the unusually slow DDR1 activation kinetics.

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c-kit associated with the transmembrane 4 superfamily proteins constitutes a functionally distinct subunit in human hematopoietic progenitors

Blood ◽

10.1182/blood.v99.12.4413 ◽

2002 ◽

Vol 99 (12) ◽

pp. 4413-4421 ◽

Cited By ~ 36

Author(s):

Naoyuki Anzai ◽

Younghee Lee ◽

Byung-S. Youn ◽

Seiji Fukuda ◽

Young-June Kim ◽

...

Keyword(s):

Tyrosine Kinase ◽

Tyrosine Phosphorylation ◽

Receptor Tyrosine Kinase ◽

Kinase Activity ◽

Myeloid Cell ◽

Hematopoietic Progenitors ◽

Modulate Function ◽

Kit Receptor ◽

Wide Range ◽

Transmembrane 4 Superfamily

The transmembrane 4 superfamily (TM4SF) has come into prominence for its association with a wide range of cell surface molecules, especially integrins. We report that TM4SF molecules CD9, CD63, and CD81 are physically associated with c-kit receptor tyrosine kinase in the human factor–dependent myeloid cell line, MO7e. We characterized this complex using coimmunoprecipitation and colocalization methods. The c-kit coimmunoprecipitated with anti-TM4SF antibodies showed several distinct phenotypes compared to the total c-kit immunoprecipitated with anti–c-kit antibody. These included: (1) higher basal level of tyrosine phosphorylation without elevated kinase activity in the absence of Steel factor (SLF), (2) deficient enhancement of tyrosine phosphorylation and kinase activity in response to SLF, (3) elevated binding rate of SLF shown in chemical cross-linking studies, and (4) little internalization and degradation after SLF treatment. Cocapping studies in living cells showed that c-kit colocalized with TM4SF molecules after SLF stimulation, suggesting confirmation of the biochemical data obtained by the coimmunoprecipitation studies. Colocalization of c-kit with CD81 by SLF was also observed in cord blood CD34+ cells, suggesting the existence of functional units of c-kit in TM4SF complexes in primary hematopoietic cells. This suggests that some TM4SF members may negatively modulate function of c-kit receptor tyrosine kinase and thus regulate receptor sensitivity to SLF in hematopoietic progenitors.

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N-aryl pyrido cyanine derivatives are nuclear and organelle DNA markers for two-photon and super-resolution imaging

Nature Communications ◽

10.1038/s41467-021-23019-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Kakishi Uno ◽

Nagisa Sugimoto ◽

Yoshikatsu Sato

Keyword(s):

Dna Markers ◽

Nuclear Dna ◽

Uv Light ◽

Imaging Techniques ◽

Super Resolution ◽

Stimulated Emission ◽

Organelle Dna ◽

Two Photon ◽

Wide Range ◽

Resolution Imaging

AbstractLive cell imaging using fluorescent DNA markers are an indispensable molecular tool in various biological and biomedical fields. It is a challenge to develop DNA probes that avoid UV light photo-excitation, have high specificity for DNA, are cell-permeable and are compatible with cutting-edge imaging techniques such as super-resolution microscopy. Herein, we present N-aryl pyrido cyanine (N-aryl-PC) derivatives as a class of long absorption DNA markers with absorption in the wide range of visible light. The high DNA specificity and membrane permeability allow the staining of both organelle DNA as well as nuclear DNA, in various cell types, including plant tissues, without the need for washing post-staining. N-aryl-PC dyes are also highly compatible with a separation of photon by lifetime tuning method in stimulated emission depletion microscopy (SPLIT-STED) for super-resolution imaging as well as two-photon microscopy for deep tissue imaging, making it a powerful tool in the life sciences.

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A Sparse Denoising-Based Super-Resolution Method for Scanning Radar Imaging

Remote Sensing ◽

10.3390/rs13142768 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2768

Author(s):

Qiping Zhang ◽

Yin Zhang ◽

Yongchao Zhang ◽

Yulin Huang ◽

Jianyu Yang

Keyword(s):

Super Resolution ◽

Radar Imaging ◽

Superior Performance ◽

L1 Norm ◽

Antenna Aperture ◽

Resolution Method ◽

Strong Point ◽

Wide Range ◽

Resolution Imaging ◽

Azimuth Resolution

Scanning radar enables wide-range imaging through antenna scanning and is widely used for radar warning. The Rayleigh criterion indicates that narrow beams of radar are required to improve the azimuth resolution. However, a narrower beam means a larger antenna aperture. In practical applications, due to platform limitations, the antenna aperture is limited, resulting in a low azimuth resolution. The conventional sparse super-resolution method (SSM) has been proposed for improving the azimuth resolution of scanning radar imaging and achieving superior performance. This method uses the L1 norm to represent the sparse prior of the target and solves the L1 regularization problem to achieve super-resolution imaging under the regularization framework. The resolution of strong-point targets is improved efficiently. However, for some targets with typical shapes, the strong sparsity of the L1 norm treats them as strong-point targets, resulting in the loss of shape characteristics. Thus, we can only see the strong points in its processing results. However, in some applications that need to identify targets in detail, SSM can lead to false judgments. In this paper, a sparse denoising-based super-resolution method (SDBSM) is proposed to compensate for the deficiency of traditional SSM. The proposed SDBSM uses a sparse minimization scheme for denoising, which helps to reduce the influence of noise. Then, the super-resolution imaging is achieved by alternating iterative denoising and deconvolution. As the proposed SDBSM uses the L1 norm for denoising rather than deconvolution, the strong sparsity constraint of the L1 norm is reduced. Therefore, it can effectively preserve the shape of the target while improving the azimuth resolution. The performance of the proposed SDBSM was demonstrated via simulation and real data processing results.

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Wavelet Based Restoration of Images with Missing or Damaged Pixels

East Asian Journal on Applied Mathematics ◽

10.4208/eajam.020310.240610a ◽

2011 ◽

Vol 1 (2) ◽

pp. 108-131 ◽

Cited By ~ 10

Author(s):

Hui Ji ◽

Zuowei Shen ◽

Yuhong Xu

Keyword(s):

Image Restoration ◽

Impulsive Noise ◽

Image Inpainting ◽

Super Resolution ◽

Image Deblurring ◽

Tight Frame ◽

Split Bregman ◽

Wide Range ◽

Resolution Imaging ◽

Degraded Images

AbstractThis paper addresses the problem of how to restore degraded images where the pixels have been partly lost during transmission or damaged by impulsive noise. A wide range of image restoration tasks is covered in the mathematical model considered in this paper - e.g. image deblurring, image inpainting and super-resolution imaging. Based on the assumption that natural images are likely to have a sparse representation in a wavelet tight frame domain, we propose a regularization-based approach to recover degraded images, by enforcing the analysis-based sparsity prior of images in a tight frame domain. The resulting minimization problem can be solved efficiently by the split Bregman method. Numerical experiments on various image restoration tasks - simultaneously image deblurring and inpainting, super-resolution imaging and image deblurring under impulsive noise - demonstrated the effectiveness of our proposed algorithm. It proved robust to mis-detection errors of missing or damaged pixels, and compared favorably to existing algorithms.

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Recent Advances in the Role of Discoidin Domain Receptor Tyrosine Kinase 1 and Discoidin Domain Receptor Tyrosine Kinase 2 in Breast and Ovarian Cancer

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.747314 ◽

2021 ◽

Vol 9 ◽

Author(s):

Li Chen ◽

Xiangyi Kong ◽

Yi Fang ◽

Shishir Paunikar ◽

Xiangyu Wang ◽

...

Keyword(s):

Ovarian Cancer ◽

Tyrosine Kinase ◽

Ligand Binding ◽

Receptor Tyrosine Kinase ◽

Tyrosine Kinases ◽

Kinase Activity ◽

Receptor Tyrosine Kinases ◽

Breast And Ovarian Cancer ◽

Discoidin Domain Receptor

Discoidin domain receptor tyrosine kinases (DDRs) are a class of receptor tyrosine kinases (RTKs), and their dysregulation is associated with multiple diseases (including cancer, chronic inflammatory conditions, and fibrosis). The DDR family members (DDR1a-e and DDR2) are widely expressed, with predominant expression of DDR1 in epithelial cells and DDR2 in mesenchymal cells. Structurally, DDRs consist of three regions (an extracellular ligand binding domain, a transmembrane domain, and an intracellular region containing a kinase domain), with their kinase activity induced by receptor-specific ligand binding. Collagen binding to DDRs stimulates DDR phosphorylation activating kinase activity, signaling to MAPK, integrin, TGF-β, insulin receptor, and Notch signaling pathways. Abnormal DDR expression is detected in a range of solid tumors (including breast, ovarian, cervical liver, gastric, colorectal, lung, and brain). During tumorigenesis, abnormal activation of DDRs leads to invasion and metastasis, via dysregulation of cell adhesion, migration, proliferation, secretion of cytokines, and extracellular matrix remodeling. Differential expression or mutation of DDRs correlates with pathological classification, clinical characteristics, treatment response, and prognosis. Here, we discuss the discovery, structural characteristics, organizational distribution, and DDR-dependent signaling. Importantly, we highlight the key role of DDRs in the development and progression of breast and ovarian cancer.

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Collagen induces activation of DDR1 through lateral dimer association and phosphorylation between dimers

eLife ◽

10.7554/elife.25716 ◽

2017 ◽

Vol 6 ◽

Cited By ~ 24

Author(s):

Victoria Juskaite ◽

David S Corcoran ◽

Birgit Leitinger

Keyword(s):

Receptor Tyrosine Kinase ◽

Drug Target ◽

Kinase Activity ◽

Transmembrane Domain ◽

Activation Mechanism ◽

Collagen Binding ◽

Wide Range ◽

Different Types ◽

In Trans ◽

Discoidin Domain Receptor 1

The collagen-binding receptor tyrosine kinase DDR1 (discoidin domain receptor 1) is a drug target for a wide range of human diseases, but the molecular mechanism of DDR1 activation is poorly defined. Here we co-expressed different types of signalling-incompetent DDR1 mutants (‘receiver’) with functional DDR1 (‘donor’) and demonstrate phosphorylation of receiver DDR1 by donor DDR1 in response to collagen. Making use of enforced covalent DDR1 dimerisation, which does not affect receptor function, we show that receiver dimers are phosphorylated in trans by the donor; this process requires the kinase activity of the donor but not that of the receiver. The receiver ectodomain is not required, but phosphorylation in trans is abolished by mutation of the transmembrane domain. Finally, we show that mutant DDR1 that cannot bind collagen is recruited into DDR1 signalling clusters. Our results support an activation mechanism whereby collagen induces lateral association of DDR1 dimers and phosphorylation between dimers.

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Multi-modal imaging reveals dynamic interactions of Staphylococcus aureus within human neutrophils

10.1101/2021.03.05.434126 ◽

2021 ◽

Author(s):

Yin Xin Ho ◽

Elliot Steele ◽

Lynne Prince ◽

Ashley Cadby

Keyword(s):

Staphylococcus Aureus ◽

Imaging Modality ◽

Super Resolution ◽

Cellular Level ◽

Innate Immune ◽

Human Neutrophils ◽

Dynamic Interactions ◽

Wide Range ◽

Resolution Imaging ◽

Super Resolution Microscopy

Staphylococcus aureus is an important human pathogen that causes a wide range of infections. Neutrophils are an essential component of our innate immune system and understanding S. aureus-neutrophil interactions on a sub-cellular level is crucial to developing new therapeutic strategies to promote immunity during S. aureus infections. To this end we have developed a multi-modal imaging platform capable of following host-pathogen processes in biological systems, this is achieved by switching imaging modalities between a low photo-toxicity and low resolution imaging modality through an increasing illumination intensity to achieve live super-resolution imaging. This novel imaging platform was applied to the study of human neutrophils infected by S. aureus. We show that we can image different infection stages of S. aureus in live neutrophils with super resolution microscopy. We see evidence of binary fission occurring in intracellular S. aureus within a neutrophil.

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