In order to elucidate a part of calmodulin actions in the hyperproliferative state in human epidermis, calmodulin activities in the psoriatic and in the normal human epidermis were determined using calmodulin-deficient phosphodiesterase from bovine heart and purified pig skin epidermal calmodulin as a standard. Skin samples were obtained from 11 normal healthy controls and from both the uninvol...

The genotoxic carcinogen aflatoxin B1 (AFB1) inhibited the calmodulin-stimulated membrane-bound (Ca2+Mg2+)-ATPase. Using the purified enzyme, 12 nmoles per ml of AFB1 caused maximum inhibition of 28% and 50%, of the acidic phospholipid-stimulated and calmodulin-activated Ca(2+)-ATPase activity respectively. Treatment of red cell ghosts with increasing concentrations of Triton X-100, a non-ionic...

Initial autophosphorylation of multifunctional Ca2+/calmodulin-dependent protein kinase (CaM kinase) occurs at Thr286 (the "autonomy" site) and converts the kinase from a Ca(2+)-dependent to a partially Ca(2+)-independent or autonomous enzyme. After removal of Ca2+/calmodulin, the autonomous kinase undergoes a "burst" of inhibitory autophosphorylation at sites distinct from the autonomy site wh...

Structure of calmodulin in solution was studied by measurements of the far UV CD spectrum. The CD spectrum of Ca?+-saturated calmodulin obtained at pH 7.0 was superimposed on the one at pH 5.6. Therefore, the structure of calmodulin at pH 7.0 may be identical to the crystalline structure determined at pH 5.6.1) The of-helix content of Ca`'+-free calmodulin was 18% lower than that of CaJ+-satura...

As a calcium-sensing protein, calmodulin acts as a transducer of the intracellular calcium signal for a variety of cellular responses. Although calcium is an important regulator of neuronal survival during development of the nervous system and is also implicated in the pathogenesis of neurodegenerative disorders, it is not known if calmodulin mediates these actions of calcium. To determine the ...

Ophiobolin A, a fungal metabolite and a phytotoxin which can stimulate the net leakage of electrolytes and glucose from maize seedling roots (Tipton, C. L., Paulsen, P. V., and Betts, R. E. (1977) Plant Physiol. 59, 907-910) was found to be a potent inhibitor of calmodulin-activated cyclic nucleotide phosphodiesterase. The physiologically less active analogue, 3-anhydro-ophiobolin A, was found ...

Calmodulin has been radioiodinated by the BoltonHunter procedure. This procedure results in incorporation of 1.5 mol of ‘251/mol of protein and yields a specific radioactivity of 2400 Ci/mmol. The radioiodinated calmodulin retains complete biological activity as determined by its ability to activate calmodulindeficient cyclic nucleotide phosphodiesterase from rat brain. A sensitive radioimmunoa...

Structure-activity studies of tetramethinemerocyanine fluorophores enabled the synthesis of novel dyes which showed spectral changes during reversible, calcium-dependent association with calmodulin. These spectral changes were greatly enhanced in dyes with a quaternary nitrogen and specifically placed hydrophobic chains. One such dye was covalently attached to calmodulin, producing a calmodulin...

The effect of bovine brain calmodulin on the assembly of pure bovine brain tubulin has been examined in the presence and absence of microtubule-associated proteins (MAPs). In the absence of MAPs, calmodulin enhances the rate and extent of polymerization of pure tubulin, probably by sequestering Ca2+ from tubulin since the effect is mimicked by ethylene glycol bis(beta-aminoethyl ether)N,N,N',N'...

We measured the concentration of calmodulin required to reverse inhibition by caldesmon of actin-activated myosin MgATPase activity, in a model smooth-muscle thin-filament system, reconstituted in vitro from purified vascular smooth-muscle actin, tropomyosin and caldesmon. At 37 degrees C in buffer containing 120 mM-KCl, 4 microM-Ca2+-calmodulin produced a half-maximal reversal of caldesmon inh...