Papers by Carolina Verdejo Otero
The Journal of Immunology, Aug 15, 2006
The chemokine receptor CCR7 and its ligands CCL19 and CCL21 play a crucial role for the homing of... more The chemokine receptor CCR7 and its ligands CCL19 and CCL21 play a crucial role for the homing of lymphocytes and dendritic cells to secondary lymphoid tissues. Nevertheless, how CCR7 senses the gradient of chemokines and how migration is terminated are poorly understood. In this study, we demonstrate that CCR7(-GFP) is endocytosed into early endosomes containing transferrin receptor upon CCL19 binding, but less upon CCL21 triggering. Internalization of CCR7 was independent of lipid rafts but relied on dynamin and Eps15 and was inhibited by hypertonic sucrose, suggesting clathrin-dependent endocytosis. After chemokine removal, internalized CCR7 recycled back to the plasma membrane and was able to mediate migration again. In contrast, internalized CCL19 was sorted to lysosomes for degradation, showing opposite fate for endocytosed CCR7 and its ligand.
Current Pharmaceutical Biotechnology, 2014
Recent advances in nanotechnology and nanobiotechnology have contributed to the development of na... more Recent advances in nanotechnology and nanobiotechnology have contributed to the development of nanomaterials, able to be used as drug carriers, probes, targets or cytostatic drugs by itself. Nanomedicine is now the leading area in nanotechnology where a large number and types of nanoparticles (NPs) has been developed and several are already in the clinical practice. Chemotherapy is one of the most widely used strategies to treat cancer. Most chemotherapeutic agents have poor solubility, low bioavailability, and are formulated with toxic solvents. NPs have been designed to overcome the lack of specificity of chemotherapeutic agents as well to improve circulation time in blood, taking advantages on tumor cells characteristics. In immunology, recent advances regarding the activation of the innate immune system artificially enhanced by NPs functionalized with immune-stimulators open a new window as novel methods in vaccines. Also, viruses and virus-like particles (VLPs) engineered to stimulate immune response against their similar virus or as molecular platforms for the presentation of foreign epitopes have been described. In this review we focused in the use of different types of NPs in oncology and immunology, pinpointing the main novelties regarding their development and use of nanotechnology in a broad array of applications, ranging from tumor diagnostics, immune-modulation up to cancer therapeutics.
PLoS ONE, 2012
In neuronal cells the intracellular trafficking machinery controls the availability of neurotrans... more In neuronal cells the intracellular trafficking machinery controls the availability of neurotransmitter receptors at the plasma membrane, which is a critical determinant of synaptic strength. Metabotropic c amino-butyric acid (GABA) type B receptors (GABA B Rs) are neurotransmitter receptors that modulate synaptic transmission by mediating the slow and prolonged responses to GABA. GABA B Rs are obligatory heteromers constituted by two subunits, GABA B R1 and GABA B R2. GABA B R1a and GABA B R1b are the most abundant subunit variants. GABA B R1b is located in the somatodendritic domain whereas GABA B R1a is additionally targeted to the axon. Sushi domains located at the N-terminus of GABA B R1a constitute the only difference between both variants and are necessary and sufficient for axonal targeting. The precise targeting machinery and the organelles involved in sorting and transport have not been described. Here we demonstrate that GABA B Rs require the Golgi apparatus for plasma membrane delivery but that axonal sorting and targeting of GABA B R1a operate in a pre-Golgi compartment. In the axon GABA B R1a subunits are enriched in the endoplasmic reticulum (ER), and their dynamic behavior and colocalization with other secretory organelles like the ER-to-Golgi intermediate compartment (ERGIC) suggest that they employ a local secretory route. The transport of axonal GABA B R1a is microtubule-dependent and kinesin-1, a molecular motor of the kinesin family, determines axonal localization. Considering that progression of GABA B Rs through the secretory pathway is regulated by an ER retention motif our data contribute to understand the role of the axonal ER in non-canonical sorting and targeting of neurotransmitter receptors.
PLoS ONE, 2013
The epidermal growth factor receptor is involved in morphogenesis, proliferation and cell migrati... more The epidermal growth factor receptor is involved in morphogenesis, proliferation and cell migration. Its up-regulation during tumorigenesis makes this receptor an interesting therapeutic target. In the absence of the ligand, the inhibition of phosphatidic acid phosphohydrolase activity by propranolol treatment leads to internalization of empty/inactive receptors. The molecular events involved in this endocytosis remain unknown. Here, we quantified the effects of propranolol on the mobility of single quantum-dot labelled receptors before the actual internalization took place. The single receptors showed a clear stop-and-go motion; their diffusive tracks were continuously interrupted by subsecond stalling events, presumably caused by transient clustering. In the presence of propranolol we found that: i) the diffusion rate reduced by 22 %, which indicates an increase in drag of the receptor. Atomic force microscopy measurements did not show an increase of the effective membrane tension, such that clustering of the receptor remains the likely mechanism for its reduced mobility. ii) The receptor got frequently stalled for longer periods of multiple seconds, which may signal the first step of the internalization process.
Molecular Biology of the Cell, 2010
Here we show that it can also control the cell surface versus intracellular distribution of empty... more Here we show that it can also control the cell surface versus intracellular distribution of empty/inactive EGFR. Our previous observation that PKA inhibitors induce EGFR internalization prompted us to test phosphatidic acid (PA) generated by phospholipase D (PLD) as an endogenous down-regulator of PKA activity, which activates rolipram-sensitive type 4 phosphodiesterases (PDE4) that degrade cAMP. We found that inhibition of PA hydrolysis by propranolol, in the absence of ligand, provokes internalization of inactive (neither tyrosine-phosphorylated nor ubiquitinated) EGFR, accompanied by a transient increase in PA levels and PDE4s activity. This EGFR internalization is mimicked by PA micelles and is strongly counteracted by PLD2 silencing, rolipram or forskolin treatment, and PKA overexpression. Accelerated EGFR endocytosis seems to be mediated by clathrin-dependent and -independent pathways, leading to receptor accumulation in juxtanuclear recycling endosomes, also due to a decreased recycling. Internalized EGFR can remain intracellular without degradation for several hours or return rapidly to the cell surface upon discontinuation of the stimulus. This novel regulatory mechanism of EGFR, also novel function of signaling PA, can transmodulate receptor accessibility in response to heterologous stimuli.
The Journal of Immunology, 2006
The chemokine receptor CCR7 and its ligands CCL19 and CCL21 play a crucial role for the homing of... more The chemokine receptor CCR7 and its ligands CCL19 and CCL21 play a crucial role for the homing of lymphocytes and dendritic cells to secondary lymphoid tissues. Nevertheless, how CCR7 senses the gradient of chemokines and how migration is terminated are poorly understood. In this study, we demonstrate that CCR7(-GFP) is endocytosed into early endosomes containing transferrin receptor upon CCL19 binding, but less upon CCL21 triggering. Internalization of CCR7 was independent of lipid rafts but relied on dynamin and Eps15 and was inhibited by hypertonic sucrose, suggesting clathrin-dependent endocytosis. After chemokine removal, internalized CCR7 recycled back to the plasma membrane and was able to mediate migration again. In contrast, internalized CCL19 was sorted to lysosomes for degradation, showing opposite fate for endocytosed CCR7 and its ligand.
Journal of Cell Science, 2008
Journal of Cell Science, 2012
The chemokine receptor CCR7 is essential for lymphocyte and dendritic cell homing to secondary ly... more The chemokine receptor CCR7 is essential for lymphocyte and dendritic cell homing to secondary lymphoid organs. Due to the ability to induce directional migration, CCR7 and its ligands CCL19 and CCL21 are pivotal for the regulation of the immune system. Here, we identified a novel function for receptor ubiquitylation in the regulation of the trafficking process of this G protein-coupled seven transmembrane receptor. We discovered that CCR7 is ubiquitylated in a constitutive, ligand-independent manner and that receptor ubiquitylation regulates the basal trafficking of CCR7 in the absence of chemokine. Upon CCL19 binding, we show that internalised CCR7 recycles back to the plasma membrane via the trans-Golgi network. An ubiquitylation-deficient CCR7 mutant internalised normally after ligand binding, but inefficiently recycled in immune cells and was transiently retarded in the TGN compartment of HEK293 transfectants. Finally, we demonstrate that the lack of CCR7 ubiquitylation profoundly impaired immune cell migration. Our results provide evidence for a novel function of receptor ubiquitylation in the regulation of CCR7 recycling and immune cell migration. L. M. and Bonifacino, J. S. (2000). GGAs: a family of ADP ribosylation factor-binding proteins related to adaptors and associated with the Golgi complex. J Cell Biol 149, 81-94. and Stankova, J. (2003). Trafficking, ubiquitination, and down-regulation of the human platelet-activating factor receptor. J Biol Chem 278, 48228-35. Escola, J. M., Kuenzi, G., Gaertner, H., Foti, M. and Hartley, O. (2010). CC chemokine receptor 5 (CCR5) desensitization: cycling receptors accumulate in the trans-Golgi network.
Fundamental & Clinical Pharmacology, 2014
Since its discovery, cAMP has been proposed as one of the most versatile second messengers. The r... more Since its discovery, cAMP has been proposed as one of the most versatile second messengers. The remarkable feature of cAMP to tightly control highly diverse physiological processes, including metabolism, homeostasis, secretion, muscle contraction, cell proliferation and migration, immune response, and gene transcription, is reflected by millions of different articles worldwide. Compartmentalization of cAMP in space and time, maintained by mainly phosphodiesterases, contributes to the maintenance of equilibrium inside the cell where one signal can trigger many different events. Novel cAMP sensors seem to carry out certain unexpected signaling properties of cAMP and thereby to permit delicate adaptations of biologic responses. Measuring space and time events with biosensors will increase our current knowledge on the pathophysiology of diseases, such as chronic obstructive pulmonary disease, asthma, cognitive impairment, cancer, and renal and heart failure. Further insights into the cAMP dynamics will help to optimize the pharmacological treatment for these diseases.
EMBO reports, 2007
Proteins bearing an endoplasmic reticulum (ER) leader are inserted into the ER followed by cleava... more Proteins bearing an endoplasmic reticulum (ER) leader are inserted into the ER followed by cleavage of the signal peptide. Major histocompatibility complex class I-restricted T-cell epitopes can be generated from these proteins by the proteasome after retrotranslocation into the cytosol. Here, we show that an HLA-A*0201-restricted epitope from prostate stem cell antigen contains the cleavage site of the ER signal peptidase. The resulting cleavage products fail to bind to HLA-A*0201 and are not recognized by T lymphocytes. As processing of prostate stem cell antigen by signal peptidase occurs immediately after cotranslational insertion, the epitope must be processed from polypeptides that have never reached the ER. The processing of this epitope depends on the proteasome and the transporter associated with antigen processing and shows a novel pathway of class I processing that relies on the failure of ER-targeted proteins to reach their target compartment.
UAM Ediciones y Editorial UCA son miembros de la UNE, lo que garantiza la difusión y comercializa... more UAM Ediciones y Editorial UCA son miembros de la UNE, lo que garantiza la difusión y comercialización de sus publicaciones a nivel na cional e internacional UAM Ediciones and Editorial UCA are the UNE members, which ensures the diffusion and com mercialization of its publications at the national and international level agraDECiMiEnTOS
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Papers by Carolina Verdejo Otero