Changes in calcium-dependent protein kinase activity during in vitro tuberization in potato

A soluble Ca2+-dependent protein kinase (CDPK) was purified to homogeneity in potato (Solanum tuberosum L.) plants. Potato CDPK was strictly dependent on Ca2+ (one-half maximal activation 0.6 μM) and phosphorylated a wide diversity of substrates, in which Syntide 2 was the best phosphate acceptor (M...

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Detalles Bibliográficos
Autor principal: Raíces, Marcela
Publicado: 1996
Materias:
Glycine max
Solanum tuberosum
Tuberosum
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00320889_v112_n4_p1541_MacIntosh
http://hdl.handle.net/20.500.12110/paper_00320889_v112_n4_p1541_MacIntosh
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00320889_v112_n4_p1541_MacIntosh
record_format dspace
spelling paper:paper_00320889_v112_n4_p1541_MacIntosh2023-06-08T14:59:58Z Changes in calcium-dependent protein kinase activity during in vitro tuberization in potato Raíces, Marcela Glycine max Solanum tuberosum Tuberosum A soluble Ca2+-dependent protein kinase (CDPK) was purified to homogeneity in potato (Solanum tuberosum L.) plants. Potato CDPK was strictly dependent on Ca2+ (one-half maximal activation 0.6 μM) and phosphorylated a wide diversity of substrates, in which Syntide 2 was the best phosphate acceptor (Michaelis constant = 30 μM). The kinase was inhibited by Ca2+- chelating agents, phenotiazine derivatives, and N-(6-aminohexyl)-5-chloro-1- naphthalenesulfonamide (one-half maximal inhibition = 0.25 mM). Polyclonal antibodies directed against the regulatory region of the soybean CDPK recognized a 53-kD polypeptide. In an autophosphorylation assay, this same band was strongly labeled with [γ-32P]ATP in the presence of Ca2+. CDPK activity was high in nontuberized plants, but increased 2.5-fold at the onset of tuber development and was reduced to one-half of its original activity when the tuber had completed formation. In the early stages of tuberization, Ca2+-dependent phosphorylation of endogenous targets (specific bands of 68, 51, and 46 kD) was observed. These polypeptides were not labeled in nontuberizing plants or in completely formed tubers, indicating that this phosphorylation is a stage-specific event. In addition, dephosphorylation of specific polypeptides was detected in tuberizing plants, suggesting the involvement of a phosphatase. Preincubation of crude extracts with phosphatase inhibitors rendered a 100% increase in CDPK activity. Fil:Raíces, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 1996 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00320889_v112_n4_p1541_MacIntosh http://hdl.handle.net/20.500.12110/paper_00320889_v112_n4_p1541_MacIntosh
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Glycine max
Solanum tuberosum
Tuberosum
spellingShingle Glycine max
Solanum tuberosum
Tuberosum
Raíces, Marcela
Changes in calcium-dependent protein kinase activity during in vitro tuberization in potato
topic_facet Glycine max
Solanum tuberosum
Tuberosum
description A soluble Ca2+-dependent protein kinase (CDPK) was purified to homogeneity in potato (Solanum tuberosum L.) plants. Potato CDPK was strictly dependent on Ca2+ (one-half maximal activation 0.6 μM) and phosphorylated a wide diversity of substrates, in which Syntide 2 was the best phosphate acceptor (Michaelis constant = 30 μM). The kinase was inhibited by Ca2+- chelating agents, phenotiazine derivatives, and N-(6-aminohexyl)-5-chloro-1- naphthalenesulfonamide (one-half maximal inhibition = 0.25 mM). Polyclonal antibodies directed against the regulatory region of the soybean CDPK recognized a 53-kD polypeptide. In an autophosphorylation assay, this same band was strongly labeled with [γ-32P]ATP in the presence of Ca2+. CDPK activity was high in nontuberized plants, but increased 2.5-fold at the onset of tuber development and was reduced to one-half of its original activity when the tuber had completed formation. In the early stages of tuberization, Ca2+-dependent phosphorylation of endogenous targets (specific bands of 68, 51, and 46 kD) was observed. These polypeptides were not labeled in nontuberizing plants or in completely formed tubers, indicating that this phosphorylation is a stage-specific event. In addition, dephosphorylation of specific polypeptides was detected in tuberizing plants, suggesting the involvement of a phosphatase. Preincubation of crude extracts with phosphatase inhibitors rendered a 100% increase in CDPK activity.
author Raíces, Marcela
author_facet Raíces, Marcela
author_sort Raíces, Marcela
title Changes in calcium-dependent protein kinase activity during in vitro tuberization in potato
title_short Changes in calcium-dependent protein kinase activity during in vitro tuberization in potato
title_full Changes in calcium-dependent protein kinase activity during in vitro tuberization in potato
title_fullStr Changes in calcium-dependent protein kinase activity during in vitro tuberization in potato
title_full_unstemmed Changes in calcium-dependent protein kinase activity during in vitro tuberization in potato
title_sort changes in calcium-dependent protein kinase activity during in vitro tuberization in potato
publishDate 1996
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00320889_v112_n4_p1541_MacIntosh
http://hdl.handle.net/20.500.12110/paper_00320889_v112_n4_p1541_MacIntosh
work_keys_str_mv AT raicesmarcela changesincalciumdependentproteinkinaseactivityduringinvitrotuberizationinpotato
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