IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Further characterization of the O-glycosylation process and its importance in root hair growth
Autor/es:
VELASQUEZ SM; SALGADO SALTER J; GLOAZZO DOROSZ J; ESTEVEZ JM
Lugar:
Mar del Plata
Reunión:
Congreso; Further characterization of the O-glycosylation process and its importance in root hair growth; 2012
Institución organizadora:
. XXIX Reunión Argentina de Fisiología Vegetal
Resumen:
O-glycosylation is a post-translational modification typically found in the plant kingdom. In this process, firstly, we have the conversion of proline residues to hydroxiproline one, done by the Prolyl-4-hydroxilases, then comes the addition of polysaccharide chains, carried out by glycosyltransferases; the final result is Highly Rich Glycosylated Proteins, like Extensins (EXTs). Prior results from this group have demonstrated the importance of O-glycosylation in polarized growth. Three P4Hs, 2 arabinosyltransferases and several EXTs were observed to be involved in root hair growth. In this present work, we have tried to go further in characterizing this post-translational modification.We were able to obtain double and triple mutants of the 3 P4Hs previously studied. These mutants helped us better understand if there is genetic redundancy between the P4Hs. P4H2 and P4H13 would be similar while P4H5 would be slightly different. Those results were further supported by the inability of P4H2 and P4H13 to complement the short root hair phenotype of P4H5, while they in turn are able to complement one another‘s short root hair phenotype. Through Mass Spec analysis we were able to infer which of the 2 arabinosyltransferases add which of the 2-5 arabinoside residues that the EXTs posses. Also, through co-localization experiments we established their subcellular localization to be at the Golgi Apparatus. Furthermore, another arabinosyltransferase was identified, GT 47 EXAD, who would be adding the fourth arabinoside residue. Finally, with the aid of Molecular dynamics of extensins peptides we observed that a correct O-glycosylation process would give the EXTs the necessary rigidity to form their network at the cell wall thereby contributing to the growth of the root hairs. All of these results help us increase the knowledge of polarized growth and further ascertain the crucial role of O-glycosylation and all of the different actors involved in that process.