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Thesis defense – Ana Dorrego-Rivas

26 March 2021 / 14:00

Venue: Centre Broca (restricted) and onzoom (link on request)

Title: Revisiting neuronal polarity in the context of PCP

Defense in english

Thesis surpervisor: Jérôme Ezan


The axonal initial segment (AIS) is a neuronal subdomain that coordinates the axo-dendritic polarity establishment and maintenance and constitutes the site for action potential tuning. The AIS structure relies on a highly organized cytoskeleton and associated molecules like Ankyrin-G (AnkG) and βIV spectrin. AnkG is the AIS master organizer, since it arrives to the proximal axon and recruits all the AIS components. The early steps of AIS assembly are still unknown, notably because of few identified AnkG partners.

Planar cell polarity (PCP) signaling controls tissue morphogenesis and cell polarity by modulating the cytoskeleton. It has important functions during nervous system development but its specific role in neurons remains unexplored. We found that some PCP proteins accumulate at the AIS in early and late stages of neuronal development, and colocalize with the main AIS members, specially AnkG, and identified new AIS protein complexes. The disruption of PCP signaling impaired AIS formation by altering the distribution and levels of the main AIS markers and disrupted the periodic actin cytoskeleton organization.

Our data identifies new players in AIS formation and composition and reveals novel mechanisms in neuronal polarity and function.

Key words: neuronal polarity, planar cell polarity, axon initial segment


Lubiana T, Weber S, Andrade Paranhos B, Araujo D, Dorrego-Rivas A, Franzen D, Nogueira Vicosa G, Ghosh A and Hojas Garcia-Plaza I. ANN: a platform to annotate text with wikidata IDs (2020, preprinted).


François George, University of Bordeaux, Président

Monica Sousa, University of Porto, Rapporteur

Matthew Grubb, King’s College London, Rapporteur

Maren Engelhardt, University of Heidelberg, Examinateur

Mireille Montcouquiol, University of Bordeaux, Invitée

Ana Dorrego-Rivas
Team Montcouquiol-Sans
Neurocentre Magendie

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26 March 2021
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