Protein kinase-dependent Kv1.3 biology

dc.contributor
Universitat de Barcelona. Departament de Bioquímica i Biomedicina Molecular
dc.contributor.author
Estadella Pérez, Irene
dc.date.accessioned
2023-02-02T10:38:33Z
dc.date.available
2024-01-20T23:45:25Z
dc.date.issued
2023-01-20
dc.identifier.uri
http://hdl.handle.net/10803/687564
dc.description
Programa de Doctorat en Biomedicina
ca
dc.description.abstract
[eng] The voltage gated potassium channel Kv1.3 is a transmembrane protein that selectively drives potassium ions participating in the electrochemical gradient of cell membranes. This channel presents a wide distribution within the body, thereby playing an important role in several physiological processes, such as regulating the cell volume, proliferation and apoptosis, and leukocyte activation. Of particular interest in this dissertation is the role of Kv1.3 in the immune system, where its activity is crucial to initiate the immune response. Moreover, an increased and/or delocalized expression of the channel is observed at the onset of autoimmune diseases pointing Kv1.3 as a potential therapeutic target. In this contest, the study of the mechanisms involved in the modulation of the amount of Kv1.3 at the plasma membrane deserves considerable attention. Kv1.3 activity mostly relies in its abundance and proper plasma membrane location, which is tightly regulated by a balance between the forward trafficking and the endocytic machinery. Thus, the control of channel internalization and degradation influences the inflammatory response. The endocytosis of Kv1.3 has been extensively studied in our laboratory and we claim that ubiquitination mediates the internalization and further lysosomal degradation of Kv1.3 via both PKC and EGFR activation. However, the specific residues, among all Kv1.3 intracellular lysines, which play a major role in channel turnover are still unknown. Moreover, although the ubiquitin ligase Nedd4-2 has been proposed to downregulate Kv1.3 activity, there is no clue about how the interaction takes place. In this context, adenosine (ADO), an endogenous key mediator in the immune response, triggers Kv1.3 endocytosis via PKC activation. However, via its A1 and A2A receptors, ADO not only activates PKC but also PKA. The ADO-dependent Kv1.3 modulation via such differential mechanisms had not been explored yet in immune cells. For that reason, in the present work we aimed to shed light to the mechanism involved in Kv1.3 turnover and thus, provide new knowledge of the molecular physiology of the immune system. We have deciphered the molecular determinants involved in Ser/Thr kinase (PKC)- and Tyrosine kinase (EGF)-mediated Kv1.3 turnover. Activation of either pathway internalized the channel by the specific ubiquitination of the lysines K70, 84, 476, 498 and 519 which form two clusters at the amino and carboxy terminal domain of the channel. Moreover, our results suggested that these two clusters are also involved in the association between Kv1.3 and Nedd4-2. We confirmed that the Kv1.3-Nedd4-2 interaction is not direct but, a physical proximity (< 40 nm) between the proteins suggested the participation of adaptor proteins. We have also characterized the PKA-mediated Kv1.3 downregulation which, unlike PKC, did not triggered the endocytosis of the channel targeting Kv1.3 to proteasomal degradation. Moreover, the activation of PKC and PKA pathways using specific ADO receptors agonists efficiently modulate Kv1.3-mediated leukocyte physiology. Thus, ADO exerts an efficient anti-inflammatory response by the activation of two complementary and synergic signalling pathways. In conclusion, this thesis further expands the knowledge of the molecular mechanisms involved in Kv1.3 turnover. We provide an insight from the molecular determinants to the functional consequences of Kv1.3 downregulation controlling the immune response and the leukocyte physiology. Our results are of considerably physiological interest due to the combination of the multitherapeutic potential of Kv1.3 and ADO.
ca
dc.format.extent
195 p.
ca
dc.language.iso
eng
ca
dc.publisher
Universitat de Barcelona
dc.rights.license
ADVERTIMENT. Tots els drets reservats. L'accés als continguts d'aquesta tesi doctoral i la seva utilització ha de respectar els drets de la persona autora. Pot ser utilitzada per a consulta o estudi personal, així com en activitats o materials d'investigació i docència en els termes establerts a l'art. 32 del Text Refós de la Llei de Propietat Intel·lectual (RDL 1/1996). Per altres utilitzacions es requereix l'autorització prèvia i expressa de la persona autora. En qualsevol cas, en la utilització dels seus continguts caldrà indicar de forma clara el nom i cognoms de la persona autora i el títol de la tesi doctoral. No s'autoritza la seva reproducció o altres formes d'explotació efectuades amb finalitats de lucre ni la seva comunicació pública des d'un lloc aliè al servei TDX. Tampoc s'autoritza la presentació del seu contingut en una finestra o marc aliè a TDX (framing). Aquesta reserva de drets afecta tant als continguts de la tesi com als seus resums i índexs.
ca
dc.source
TDX (Tesis Doctorals en Xarxa)
dc.subject
Canals iònics
ca
dc.subject
Canales iónicos
ca
dc.subject
Ion channels
ca
dc.subject
Proteïnes
ca
dc.subject
Proteínas
ca
dc.subject
Proteins
ca
dc.subject
Ubiqüitina
ca
dc.subject
Ubicuitina
ca
dc.subject
Ubiquitin
ca
dc.subject
Cicle cel·lular
ca
dc.subject
Ciclo celular
ca
dc.subject
Cell cycle
ca
dc.subject.other
Ciències Experimentals i Matemàtiques
ca
dc.title
Protein kinase-dependent Kv1.3 biology
ca
dc.type
info:eu-repo/semantics/doctoralThesis
dc.type
info:eu-repo/semantics/publishedVersion
dc.subject.udc
577
ca
dc.contributor.director
Felipe Campo, Antonio
dc.contributor.tutor
Felipe Campo, Antonio
dc.rights.accessLevel
info:eu-repo/semantics/openAccess


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