title: Regulation of CDPK isoforms during tuber development.
abstract: CDPK activities present during tuber development were analysed. A high CDPK activity was detected in the soluble fraction of early stolons and a lower one was detected in soluble and particulate fractions of induced stolons. The early and late CDPK activities displayed diverse specificity for in vitro substrates and different subcellular distribution. Western blot analysis revealed two CDPKs of 55 and 60 kDa that follow a precise spatial and temporal profile of expression. The 55 kDa protein was only detected in early-elongating stolons and the 60 kDa one was induced upon stolon swelling, correlating with early and late CDPK activities. A new member of the potato CDPK family, StCDPK3, was identified from a stolon cDNA library. Gene specific RT-PCR demonstrated that this gene is only expressed in early stolons, while the previously identified StCDPK1 is expressed upon stolon swelling. This expression profile suggests that StCDPK3 could correspond to the 55 kDa isoform while StCDPK1 could encode the 60 kDa isoform present in swelling stolons. StCDPK1 has myristoylation and palmitoylation consensus possibly involved in its dual intracellular localization. Transient expression studies with wild-type and mutated forms of StCDPK1 fused to GFP were used to show that subcellular localization of this isoform is controlled by myristoylation and palmitoylation. Altogether, our data suggest that sequential activation of StCDPK3 and StCDPK1 and the subcellular localisation of StCDPK1 might be critical regulatory steps of calcium signalling during potato tuber development.
authors.affiliation: Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, CONICET and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Vuelta de Obligado 2490 2do piso, 1428 Buenos Aires, Argentina.
authors.forename: Marcela
authors.initials: M
authors.lastname: Raíces
authors.forename: Pablo Rubén
authors.initials: PR
authors.lastname: Gargantini
authors.forename: Delphine
authors.initials: D
authors.lastname: Chinchilla
authors.forename: Martín
authors.initials: M
authors.lastname: Crespi
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Téllez-Iñón
authors.forename: Rita María
authors.initials: RM
authors.lastname: Ulloa
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D019814:Myristic Acid / Q000378:metabolism; D010169:Palmitic Acids / Q000378:metabolism; D010940:Plant Proteins; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D011198:Solanum tuberosum / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D008164:Luminescent Proteins; D008565:Membrane Proteins; D010169:Palmitic Acids; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D019814:Myristic Acid; D049452:Green Fluorescent Proteins; D011494:Protein Kinases