Turnover of voltage-gated potassium channel kv 1.3

• Autores: Katarzyna Styrczewska
• Directores de la Tesis: Antonio Felipe Campo (dir. tes.)
• Lectura: En la Universitat de Barcelona ( España ) en 2017
• Idioma: español
• Tribunal Calificador de la Tesis: Carmen Valenzuela Miranda (presid.), Francisco J. López Soriano (secret.), Rubén Vicente García (voc.)
• Programa de doctorado: Programa de Doctorado en Biomedicina por la Universidad de Barcelona
• Materias:
  • Química
    • Bioquímica
      • Biología molecular
  • Ciencias de la vida
    • Biofísica
    • Inmunología
• Enlaces
  • Tesis en acceso abierto en: TDX
• Resumen

  • Voltage-gated K channels (Kv) is large family of channels that are expressed in both excitable and non-excitable cells. In excitable cells they contribute to the control of resting membrane potential and action potentials frequency and duration. In non-excitable tissues they are involved in many processes such as secretion to cell proliferation. Kv1.3 channel plays a key role in a wide range of physiological phenomenon. Regulation of this transmembrane protein is therefore essential for a correct function of the living cell. The balance between synthesis and degradation is highly important and must be tightly regulated. The present dissertation is focused in investigating endocytosis mechanisms of Kv1.3, as a process controlling number of the channel on the cell surface and the possible implication in cell destiny.

    We deciphered major endocytosis mechanisms triggered by EGF and Adenosine (ADO) in HeLa and HEK 293 heterologous cell systems as well as in native cell lines (macrophages, dendritic or neuronal precursor). These studies pointed out the impact of endocytosis in turnover and homeostasis of Kv1.3 and possible physiological relevance of these finding. Our experiments showed two different ways to control abundance of the Kv1.3 channel by EGF: via tyrosine phosphorylation and unconventional ERK1/2-dependent mechanisms. EGF triggered clathrin-dependent lysosomal degradation of Kv1.3. As next, PMA-induced PKC-dependent endocytosis and ubiquitination were investigated. We revealed that PMA triggered PKC-dependent ubiquitin-mediated lysosomal degradation of Kv1.3. Adenosine is an anti-inflammatory purine nucleoside that down-regulate Kv1.3 via PKC activation similar to PMA. Furthermore, we elucidate the mechanism of ADO-dependent endocytosis of Kv1.3. Our results, for the first time, provided evidence on the effect of PKA activation on the Kv1.3 trafficking. Furthermore, we were deciphering molecular determinants of Kv1.3 ubiquitination. We found that complementary and redundant lysines participate in the ubiquitin-dependent PKC and PKA regulation of Kv1.3