Arabidopsis Synaptotagmin 1 is required for the maintenance of plasma membrane integrity and cell viability

15 páginas, 6 figuras.-- et al.

Plasma membrane repair in animal cells uses synaptotagmin 7, a Ca2+-activated membrane fusion protein that mediates delivery of intracellular membranes to wound sites by a mechanism resembling neuronal Ca2+-regulated exocytosis. Here, we show that loss of function of the homologous Arabidopsis thaliana Synaptotagmin 1 protein (SYT1) reduces the viability of cells as a consequence of a decrease in the integrity of the plasma membrane. This reduced integrity is enhanced in the syt1-2 null mutant in conditions of osmotic stress likely caused by a defective plasma membrane repair. Consistent with a role in plasma membrane repair, SYT1 is ubiquitously expressed, is located at the plasma membrane, and shares all domains characteristic of animal synaptotagmins (i.e., an N terminus-transmembrane domain and a cytoplasmic region containing two C2 domains with phospholipid binding activities). Our analyses support that membrane trafficking mediated by SYT1 is important for plasma membrane integrity and plant fitness

A.L.S. was supported by a FPU fellowship from the Ministerio de Educación y Ciencia and F.B. by SAV Grant APVV-0432-06. This work was supported by funding from El Ministerio de Educación y Ciencia (Grants BIO2005-4733 and BIO2008-1709), grants from the Bundesministerium für Wirtschaft und Technologie via Deutsches Zentrum für Luft und Raumfahrt (Cologne, Germany; Project 50WB 0434), from the European Space Agency (ESA-ESTEC Noordwijk, The Netherlands; MAP Project AO-99-098), and from the Ente Cassa di Risparmio di Firenze (Italy)

Peer reviewed