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Role of alternative splicing in the biological properties of the voltage-gated potassium channel Kv10.1

dc.contributor.advisorStühmer, Walter Prof. Dr.
dc.contributor.authorRomaniello, Vincenzo
dc.titleRole of alternative splicing in the biological properties of the voltage-gated potassium channel Kv10.1de
dc.contributor.refereeHoerner, Michael Prof. Dr.
dc.description.abstractengIn the past few years, several publications highlighted the role of alternative splicing as additional source of modulation of ion channels activity. E65 and E70 (also termed as KV10.1Δ4-7 and KV10.1Δ4-9) represent two recently identified non-channel proteins derived from alternative splicing of KV10.1 voltage-gated potassium channels. The two short isoforms were identified with PCR techniques and their physiological significance was largely obscure. This thesis work primarily aimed at studying the impact of E65 and E70 on KV10.1 properties. Firstly, the expression of KV10.1 short isoforms in native system was definitely demonstrated by means of nuclease protection assays. Afterwards, occurrence of interaction between both E65 and E70 with KV10.1 was investigated: the two splice isoforms coprecipitated and colocalized with the KV10.1 full-length channel in a reconstituted system. Remarkably, E65 and E70 also occurred together with the full-length channel in the same supramolecular complex in native conditions. A robust down-regulation of ion currents through KV10.1 channels was observed when KV10.1 was co-expressed with E65 and E70. The modulation was dose-dependent and most likely specific to KV10.1 channels, since there were generally no effects on KV1.4 current. The two short isoforms affect the KV10.1 function through different mechanisms. In the case of E65, the TCC domain, although not required for the interaction between the two proteins, seems to play a critical role in the modulation of KV10.1 current. On the other hand E70 co-expression with the full-length channel impairs glycosylation of KV10.1; this would probably result in the production of ‘immature’ ion channels that, although capable of reaching the membrane, would be defective in terms of function. KV10.1 channels expression has been implicated in physiological and pathophysiological processes like cell proliferation, cell cycle and cancerogenesis. It was finally investigated whether E65 and E70 could also be involved in cell proliferation and cell cycle modulation. No obvious alterations of cell cycle profile and growth rate of KV10.1-expressing cells were observed under overexpression of E65 or E70. In conclusion, this study unequivocally demonstrated the expression of E65 and E70 in natively expressing systems and provided mechanistic insights into their modulation of KV10.1 channel function; yet further studies will be required in order to unravel the overall E65 and E70 physiological (and eventually pathophysiological)
dc.contributor.coRefereeMoser, Tobias Prof. Dr.
dc.contributor.thirdRefereePardo, Luis A. Dr.
dc.subject.engion channels+alternative splicing+Eag+glycosylation+electrophysiologyde
dc.affiliation.instituteGöttinger Graduiertenschule für Neurowissenschaften, Biophysik und molekulare Biowissenschaften (GGNB)de
dc.subject.gokfullBiologie (PPN619462639)de

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