Osmotic Stress Induces Rapid Activation of a Salicylic Acid-Induced Protein Kinase and a Homolog of Protein Kinase ASK1 in Tobacco Cells
Year: 2000
Type: article
Abstract: 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 approximately 30 min. In contrast, the 42-kD kinase was activated within 1 min after osmotic stress, and its activity was maintained for approximately 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).
Source: The Plant Cell
DOI: 10.2307/3871037
Authors: Monika Mikołajczyk, Olubunmi S. Awotunde, Grażyna Muszyńska, Daniel F. Klessig, Grażyna Dobrowolska
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2152921032