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Zebrafish yolk sac microinjection of thalidomide for assessment of developmental toxicology

Toxicological Evaluation of SiO2 Nanoparticles by Zebrafish Embryo Toxicity Test

Increased susceptibility to oxidative stress-induced toxicological evaluation by genetically modified nrf2a-deficient zebrafish.

EGF receptor kinase suppresses ciliogenesis through activation of USP8 deubiquitinase

Chemokines protect vascular smooth muscle cells from cell death induced by cyclic mechanical stretch.

tHydrophobic regions function in calmodulin-enzyme(s) interactions.


J Biol Chem. 1980 Dec 10;255(23):11078-80.

Hydrophobic regions function in calmodulin-enzyme(s) interactions.

Tanaka T, Hidaka H.


Certain naturally occurring lipids (phosphatidylinositol, phosphatidylserine, arachidonic acid) and sodium dodecyl sulfate activate at least two calmodulin-dependent enzymes, bovine brain 3':5'-cyclic nucleotide phosphodiesterase and chicken gizzard myosin light chain kinase in the absence of Ca2+. 2-p-Toluidinyl-naphthalene-6-sulfonate (TNS), which is often used as a probe for hydrophobic groups of proteins, inhibits these two calmodulin-dependent enzymes. Kinetic analysis of inhibition of chicken gizzard myosin kinase by TNS revealed a competitive fashion against calmodulin-induced activation. The interaction between TNS and purified bovine brain calmodulin as demonstrated in the appearance of TNS fluorescence in the presence of 3 microM or more of calcium ion was not observed in the presence of 2 mM EGTA. This suggests that TNS is able to bind to calmodulin in the presence of Ca2+. Moreover, a calmodulin-interacting agent N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide suppressed the TNS fluorescence induced by complex formation with calmodulin in the presence of Ca2+. These results suggest that when Ca2+ binds to the high affinity sites of calmodulin, it induces a conformational change which exposes hydrophobic groups, and the calmodulin is then capable of activating calmodulin-dependent enzymes. We propose that hydrophobic properties of Ca2+-calmodulin are important for the activation of Ca2+-calmodulin-dependent enzymes.

PMID: 6254958 [PubMed - indexed for MEDLINE]