Cytosolic glutamine synthetase and not nitrate reductase from the green alga Chlamydomonas reinhardtii is phosphorylated and binds 14-3-3 proteins

Mercedes Pozuelo; Carol MacKintosh; Aurora Galvan; Emilio Fernandez

doi:10.1007/s004250000388

Cytosolic glutamine synthetase and not nitrate reductase from the green alga Chlamydomonas reinhardtii is phosphorylated and binds 14-3-3 proteins

Mercedes Pozuelo
, Carol MacKintosh
, Aurora Galvan
, Emilio Fernandez

Research output: Contribution to journal › Article › peer-review

39 Citations (Scopus)

Abstract

The nitrate reductase activity from Chlamydomonas reinhardtii was not altered when extracts were incubated with yeast 14-3-3 proteins in the presence of Mg-ATP. However, the C. reinhardtii extracts contained 14-3-3 proteins capable of inhibiting the spinach nitrate reductase, raising the question of their physiological substrates. Two C. reinhardtii proteins of about 48 and 35 kDa were eluted from 14-3-3 affinity chromatography columns and bound to 14-3-3s in overlay assays. The 48-kDa protein corresponded to the cytosolic isoform of glutamine synthetase (GSI). The C;SI was phosphorylated by a Ca2+ and calmodulin-dependent protein kinase partially purified from the alga. How-ever, neither phosphorylation nor 14-3-3 binding seemed to change GS catalytic activity.

Original language	English
Pages (from-to)	264-269
Number of pages	6
Journal	Planta
Volume	212
Issue number	2
DOIs	https://doi.org/10.1007/s004250000388
Publication status	Published - Jan 2001

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title = "Cytosolic glutamine synthetase and not nitrate reductase from the green alga Chlamydomonas reinhardtii is phosphorylated and binds 14-3-3 proteins",

abstract = "The nitrate reductase activity from Chlamydomonas reinhardtii was not altered when extracts were incubated with yeast 14-3-3 proteins in the presence of Mg-ATP. However, the C. reinhardtii extracts contained 14-3-3 proteins capable of inhibiting the spinach nitrate reductase, raising the question of their physiological substrates. Two C. reinhardtii proteins of about 48 and 35 kDa were eluted from 14-3-3 affinity chromatography columns and bound to 14-3-3s in overlay assays. The 48-kDa protein corresponded to the cytosolic isoform of glutamine synthetase (GSI). The C;SI was phosphorylated by a Ca2+ and calmodulin-dependent protein kinase partially purified from the alga. How-ever, neither phosphorylation nor 14-3-3 binding seemed to change GS catalytic activity.",

author = "Mercedes Pozuelo and Carol MacKintosh and Aurora Galvan and Emilio Fernandez",

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T1 - Cytosolic glutamine synthetase and not nitrate reductase from the green alga Chlamydomonas reinhardtii is phosphorylated and binds 14-3-3 proteins

AU - Pozuelo, Mercedes

AU - MacKintosh, Carol

AU - Galvan, Aurora

AU - Fernandez, Emilio

PY - 2001/1

Y1 - 2001/1

N2 - The nitrate reductase activity from Chlamydomonas reinhardtii was not altered when extracts were incubated with yeast 14-3-3 proteins in the presence of Mg-ATP. However, the C. reinhardtii extracts contained 14-3-3 proteins capable of inhibiting the spinach nitrate reductase, raising the question of their physiological substrates. Two C. reinhardtii proteins of about 48 and 35 kDa were eluted from 14-3-3 affinity chromatography columns and bound to 14-3-3s in overlay assays. The 48-kDa protein corresponded to the cytosolic isoform of glutamine synthetase (GSI). The C;SI was phosphorylated by a Ca2+ and calmodulin-dependent protein kinase partially purified from the alga. How-ever, neither phosphorylation nor 14-3-3 binding seemed to change GS catalytic activity.

AB - The nitrate reductase activity from Chlamydomonas reinhardtii was not altered when extracts were incubated with yeast 14-3-3 proteins in the presence of Mg-ATP. However, the C. reinhardtii extracts contained 14-3-3 proteins capable of inhibiting the spinach nitrate reductase, raising the question of their physiological substrates. Two C. reinhardtii proteins of about 48 and 35 kDa were eluted from 14-3-3 affinity chromatography columns and bound to 14-3-3s in overlay assays. The 48-kDa protein corresponded to the cytosolic isoform of glutamine synthetase (GSI). The C;SI was phosphorylated by a Ca2+ and calmodulin-dependent protein kinase partially purified from the alga. How-ever, neither phosphorylation nor 14-3-3 binding seemed to change GS catalytic activity.

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DO - 10.1007/s004250000388

M3 - Article

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SN - 0032-0935

VL - 212

SP - 264

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JO - Planta

JF - Planta

IS - 2

ER -

Cytosolic glutamine synthetase and not nitrate reductase from the green alga Chlamydomonas reinhardtii is phosphorylated and binds 14-3-3 proteins

Abstract

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