Osmotic Stress Induces Rapid Activation of a Salicylic Acid–Induced Protein Kinase and a Homolog of Protein Kinase ASK1 in Tobacco Cells

AUTOR(ES)

Mikołajczyk, Monika

FONTE

American Society of Plant Physiologists

RESUMO

In tobacco cells, osmotic stress induced the rapid activation of two protein kinases that phosphorylate myelin basic protein. Immunological studies demonstrated that the 48-kD kinase is the salicylic acid–induced protein kinase (SIPK), a member of the mitogen-activated protein kinase family. SIPK was activated 5 to 10 min after the cells were exposed to osmotic stresses, and its activity persisted for ∼30 min. In contrast, the 42-kD kinase was activated within 1 min after osmotic stress, and its activity was maintained for ∼2 hr. Moreover, in addition to myelin basic protein, the 42-kD kinase phosphorylated casein and two transcription factors, c-Jun and ATF-2. This latter enzyme was inactivated by a serine/threonine–specific phosphatase but, unlike SIPK, was not affected by a tyrosine-specific phosphatase. After the 42-kD kinase was purified to apparent homogeneity, tryptic peptide analysis indicated that it is a homolog of Arabidopsis serine/threonine kinase1 (ASK1).

Documentos Relacionados

• Activation of Salicylic Acid–Induced Protein Kinase, a Mitogen-Activated Protein Kinase, Induces Multiple Defense Responses in Tobacco
• Calcium-Independent Activation of Salicylic Acid-Induced Protein Kinase and a 40-Kilodalton Protein Kinase by Hyperosmotic Stress1
• Analysis of stress-induced or salicylic acid-induced expression of the pathogenesis-related 1a protein gene in transgenic tobacco.
• Genetic Modification of Alternative Respiration Has Differential Effects on Antimycin A-Induced versus Salicylic Acid-Induced Resistance to Tobacco mosaic virus1
• Salicylic Acid Induces Rapid Inhibition of Mitochondrial Electron Transport and Oxidative Phosphorylation in Tobacco Cells1