Differential response of the epidermal growth factor receptor tyrosine kinase activity to several plant and mammalian lectins

Journal/Book: Molecular and Cellular Biochemistry 142, 117-124. 1995;

Abstract: Biosignalling via lectins may involve modulation of protein kinaseactivities. This aspect of the biological action of mammalian and plantlectins has been investigated for their effect on the activity of theisolated epidermal growth factor receptor (EGFR). The constitutivetyrosine kinase activity of the epidermal growth factor receptor fromrat liver, isolated by calmodulin-affinity chromatography, was activatedby concanvalin A (ConA), and wheat germ agglutinin (WGA) to a similarextent as the measured enhancement induced by EGF. In contrast, twomannose-specific lectins, the mannan-binding protein (MBP) and serumamyloid P component (SAP), isolated from human serum, have inhibitoryeffects, both in the absence and presence of EGF. The differentialeffects of these lectins were tested using as phosphorylatablesubstrates a co-polymer of glutamic acid-tyrosine, as well ascalmodulin. However, two galactoside-specific lectins, thelaminin-binding beta-galactoside-binding 14 kDa lectin, isolated frombovine heart (14K-BHL), and the alpha/beta-galactoside-binding lectin,isolated from mistletoe (Viscum album L.) leaves (VAA), do not inhibitthe EGFR tyrosine kinase activity. The sugar dependence of thelectin-mediated action was studied by inhibition assays. Mannose and amannose-containing neoglycoprotein prevent the activating effect ofConA, and N-acetyl-D-glucosamine partially prevents the activationproduced by WGA. However, mannose and mannose-containing neoglycoproteinwere ineffective to reduce the inhibitory effect of MBP or SAP.(ABSTRACTTRUNCATED AT 250 WORDS) Author.

Keyword(s): ACETYLGLUCOSAMINE/PD (pharmacology)

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