The distribution of calmodulin and Ca2+-activated calmodulin in cell cycle of mouse erythroleukemia cells

Abstract

The activation of the heme oxygenase (HO), fos, and AP-1 genes was determined at intervals after treatment of M1 cells (derived from mouse myeloleukemia) with heme or 12-O-tetradecanoylphorbol 13-acetate (TPA). On treatment with heme, M1 cells did not differentiate into macrophage but their HO gene was activated and showed maximum transcriptional activity after treatment with heme for 2 h. In contrast, on treatment with TPA, these cells adhered to the culture flasks within 5 h and differentiated into macrophage-like cells. Moreover, the sequential activation of the fos, AP-1, and HO genes was observed during this period, with the maximal transcriptional activities after TPA treatment for 0.5, 1, and 1.5 h, respectively. Thus, the HO gene was activated by treatment with either heme or TPA, and the latter activation was associated with activations of the fos and AP-1 genes. As the rat HO gene is known to have a TPA-sensitive element in its promoter region, this gene was suggested to be activated by a fos-AP-1 complex protein.

Distribution and role of calmodulin in tip growing hyphae of Saprolegnia ferax

“…Considering phenothiazine drugs could only give the information of Ca 2+ -activated CaM site and may be not completely specific to CaM [17], we further determined the distribution of total CaM in tip growing hyphae by immunohistochemical method, which could be used for the localization of both inactivated and Ca 2+ -activated CaM sites [18]. Thus, a gradient of brownish reaction product from tip to base in hyphal tips was observed (Fig 4, 5), revealing the concentration of total CaM mainly in the apex of hyphae.…”

Intracellular levels of calmodulin are increased in transformed cells

“…Neither results were based on individual cell study, We have demonstrated that intracellular CaM level was increased from G1 through S to G2M [6], Although there was a report that total protein was increased along the cell cycle too [7],it is unclear whether the increase of intracellular level of CaM represented a true increase in the total intracellular level of this protein. The present work was undertaken in order to determine whether the rise of specific activity actually represents an increase of CaM molecules per cell based on the ratio of CaM to protein in individual cells and whether such change denotes a more general response to transformation by oncogenic viruses and irradiation as well.…”