In vitro and in vivo phosphorylation of polypeptides in plasma membrane and tonoplast-enriched fractions from barley roots

Journal Article · Mon Apr 01 00:00:00 EST 1991 · Plant Physiology; (United States)

DOI:https://doi.org/10.1104/pp.95.4.1219· OSTI ID:5200877

Garbarino, J E; Hurkman, W J; Tanaka, C K; DuPont, F M ^[1]

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1. Dept. of Agriculture, Albany, CA (USA)

Phosphorylation of polypeptides in membrane fractions from barley (Hordeum vulgare L. cv CM 72) roots was compared in in vitro and in vivo assays to assess the potential role of protein kinases in modification of membrane transport. Membrane fractions enriched in endoplasmic reticulum, tonoplast, and plasma membrane were isolated using sucrose gradients and the membrane polypeptides separated using sodium dodecyl sulfate polyacrylamide gel electrophoresis. When the membrane fractions were incubated with {gamma}(p{sup 32}P)ATP, phosphorylation occurred almost exclusively in the plasma membrane fraction. Phosphorylation of a band at 38 kilodaltons increased as the concentration of Mg{sup 2+} was decreased from millimolar to micromolar levels. Phosphorylation of bands at 125, 86, 58, 46 and 28 kilodaltons required millimolar Mg{sup 2+} concentrations and was greatly enhanced by Ca{sup 2+}. When roots of intact plants were labeled with ({sup 32}P)orthophosphate, polypeptides at approximately 135, 166, 90, 46 to 53, 32, 28, and 19 kilodaltons were labeled in the plasma membrane fraction and polypeptides at approximately 73, 66, and 48 kilodaltons were labeled in the tonoplast fraction. Treatment of the roots of intact plants with 150 millimolar NaCl resulted in increased phosphorylation of some polypeptides while treatment with 100 mM NaCl had no effect.

• OSTI ID: 5200877
• Journal Information: Plant Physiology; (United States), Vol. 95:4; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BARLEY
PHYSIOLOGY
POLYPEPTIDES
PHOSPHORYLATION
ATP
CALCIUM COMPOUNDS
CELL MEMBRANES
IN VITRO
IN VIVO
MEMBRANE TRANSPORT
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHOTRANSFERASES
ROOTS
TRACER TECHNIQUES
ALKALINE EARTH METAL COMPOUNDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CELL CONSTITUENTS
CEREALS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
ENZYMES
GRAMINEAE
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LILIOPSIDA
MAGNOLIOPHYTA
MEMBRANES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PEPTIDES
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PLANTS
PROTEINS
RADIOISOTOPES
TRANSFERASES
550201* - Biochemistry- Tracer Techniques