Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.
Subscribe

Logo for

Development 132 (9): 2191-2202

The single AmphiTrk receptor highlights increased complexity of neurotrophin signalling in vertebrates and suggests an early role in developing sensory neuroepidermal cells

Èlia Benito-Gutiérrez1, Christian Nake2, Marta Llovera2, Joan X. Comella2,*, and Jordi Garcia-Fernàndez1,*,{dagger}

1 Departament de Genética, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal, 645, E-08028, Barcelona, Spain
2 Departament de Ciéncies Médiques Bàsiques, Facultat de Medicina, Universitat de Lleida, Avinguda Rovira Roure 44, E-25198, Lleida, Spain

{dagger} Author for correspondence (e-mail: jordigarcia{at}ub.edu)

Accepted for publication 24 February 2005.

Abstract: Neurotrophins (Nt) and their tyrosine kinase Trk receptors play an essential role in the development and maintenance of the complex vertebrate nervous system. Invertebrate genome sequencing projects have suggested that the Nt/Trk system is a vertebrate innovation. We describe the isolation and characterisation of the amphioxus Trk receptor, AmphiTrk. Its ancestral link to vertebrate Trk receptors is supported by phylogenetic analysis and domain characterisation. The genomic structure of AmphiTrk strongly suggests that a ProtoTrk gene emerged by means of exon-shuffling prior to the cephalochordate/vertebrate split. We also examined the physiological response of AmphiTrk to vertebrate neurotrophins, and found that despite 500 million years of divergence, AmphiTrk transduces signals mediated by NGF, BDNF, NT3 and NT4. Markedly, AmphiTrk is able to activate survival and differentiation pathways, but fails to activate the PLC{gamma} pathway, which is involved in synaptic plasticity in higher vertebrates. AmphiTrk is expressed during amphioxus embryogenesis in sensory neural precursors in the epidermis, which possesses single migratory cells. We propose that the duplication and divergence of the Nt/Trk system, in tandem with recruitment of the PLC{gamma} pathway, may have provided the genetic basis for a key aspect of vertebrate evolution: the complexity of the nervous system.

Key Words: Amphioxus • Exon shuffling • Vertebrate transition • Nervous system • Neurotrophic activity

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Ptychoderid Hemichordate Neurulation without a Notochord.
S. Luttrell, C. Konikoff, A. Byrne, B. Bengtsson, and B. J. Swalla (2012)
Integr. Comp. Biol. 52, 829-834
   Abstract »    Full Text »    PDF »
Neurosteroids and Microneurotrophins Signal Through NGF Receptors to Induce Prosurvival Signaling in Neuronal Cells.
A. Gravanis, T. Calogeropoulou, V. Panoutsakopoulou, K. Thermos, C. Neophytou, and I. Charalampopoulos (2012)
Science Signaling 5, pt8
   Abstract »    Full Text »    PDF »
BMP and Delta/Notch signaling control the development of amphioxus epidermal sensory neurons: insights into the evolution of the peripheral sensory system.
T.-M. Lu, Y.-J. Luo, and J.-K. Yu (2012)
Development 139, 2020-2030
   Abstract »    Full Text »    PDF »
Cephalochordates (Amphioxus or Lancelets): A Model for Understanding the Evolution of Chordate Characters.
J. K. S. Yu and L. Z. Holland (2009)
Cold Spring Harb Protoc 2009, pdb.emo130
   Abstract »    Full Text »    PDF »
Spliceosomal introns as tools for genomic and evolutionary analysis.
M. Irimia and S. W. Roy (2008)
Nucleic Acids Res. 36, 1703-1712
   Abstract »    Full Text »    PDF »
Neurotrophin-regulated signalling pathways.
L. F Reichardt (2006)
Phil Trans R Soc B 361, 1545-1564
   Abstract »    Full Text »    PDF »

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882