Proteolytic events are relevant cellular responses during nervous system regeneration of the starfish Marthasterias glacialis Catarina Ferraz Franco a , Romana Santos a, b , Ana Varela Coelho a, ⁎ a Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal b Unidade de Investigação em Ciências Orais e Biomédicas, Faculdade de Medicina Dentária, Universidade de Lisboa, Portugal ARTICLE INFO ABSTRACT Article history: Received 6 September 2013 Accepted 9 December 2013 Available online 14 January 2014 The molecular pathways that trigger the amazing intrinsic regenerative ability of echinoderm nervous system are still unknown. In order to approach this subject, a 2D-DIGE proteomic strategy was used, to screen proteome changes during neuronal regeneration in vivo, using starfish (Asteroidea, Echinodermata) as a model. A total of 528 proteins showed significant variations during radial nerve cord regeneration in both soluble and membrane protein- enriched fractions. Several functional classes of proteins known to be involved in axon regeneration events in other model organisms, such as chordates, were identified for the first time in the regenerating echinoderm nervous system. Unexpectedly, most of the identified proteins presented a molecular mass either higher or lower than expected. Such results suggest a functional modulation through protein post-translational modifications, such as proteolysis. Among these are proteins involved in cytoskeleton and microtubule regulators, axon guidance molecules and growth cone modulators, protein de novo synthesis machinery, RNA binding and transport, transcription factors, kinases, lipid signaling effectors and proteins with neuropro- tective functions. In summary, the impact of proteolysis during regeneration events is here shown, although requiring further studies to detail on the mechanisms involving this post- transcriptional event on nervous system regeneration. Biological significance The nervous systems of some organisms present a complete inability of neurons to regrow across a lesion site, which is the case of the adult mammalian central nervous system (CNS). Expanding our knowledge on how other animals regenerate their nervous system offers great potential for groundbreaking biomedical applications towards the enhancement of mammalian CNS regeneration. In order to approach this subject, a 2D‐DIGE proteomic strategy was used for the first time, to screen the proteome changes during neuronal regeneration in vivo, using starfish (Asteroidea, Echinodermata) as a model. We strongly believe in the relevance of our results and have clear evidences that this work constitutes a solid basis for new research on starfish regenerating nerve cord. We also believe this work will have a significant impact not only on the general scientific community as we present here an alternative animal model to neurobiology, but also on the Keywords: Regeneration Radial nerve cord Echinoderm Proteolysis DIGE Starfish JOURNAL OF PROTEOMICS 99 (2014) 1 – 25 Abbreviations: 2D-DIGE, gel difference electrophoresis; CNS, central nervous system; RNC, radial nerve cord; WH, wound healing; RG, tissue re-growth; ECM, extracellular matrix. ⁎ Corresponding author at: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157 Oeiras, Portugal. Tel.: +351 214469451; fax: +351 21441 1277. E-mail address: varela@itqb.unl.pt (A. Varela Coelho). 1874-3919/$ – see front matter © 2013 Published by Elsevier B.V. http://dx.doi.org/10.1016/j.jprot.2013.12.012 Available online at www.sciencedirect.com ScienceDirect www.elsevier.com/locate/jprot