The Role of the Time Factor in Protein Synthesis

Abstract The present study evaluated the mechanism by which protein synthesis inhibitors activate bovine oocytes. The aim was to analyze the dynamics of MPF and MAPKs. MII oocytes were activated with ionomycin (Io), ionomycin+anisomycin (ANY) and ionomycin+cycloheximide (CHX) and by in vitro fertilization (IVF). The expression of cyclin B1, p-CDK1, p-ERK1/2, p-JNK, and p-P38 were evaluated by immunodetection and the kinase activity of ERK1/2 was measured by enzyme assay. Evaluations at 1, 4, and 15 hours postactivation (hpa) showed that the expression of cyclin B1 was not modified by the treatments. ANY inactivated MPF by p-CDK1Thr14-Tyr15 at 4 hpa (P < 0.05), CHX increased pre-MPF (p-CDK1Thr161 and p-CDK1Thr14-Tyr15) at 1 hpa and IVF increased p-CDK1Thr14-Tyr15 at 17 hours postfertilization (hpf) (P < 0.05). ANY and CHX reduced the levels of p-ERK1/2 at 4 hpa (P < 0.05) and its activity at 4 and 1 hpa, respectively (P < 0.05). Meanwhile, IVF increased p-ERK1/2 at 6 hpf (P < 0.05); however, its kinase activity decreased at 6 hpf (P < 0.05). p-JNK in ANY, CHX, and IVF oocytes decreased at 4 hpa (P < 0.05). p-P38 was only observed at 1 hpa, with no differences between treatments. In conclusion, activation of bovine oocytes by ANY, CHX, and IVF inactivates MPF by CDK1-dependent specific phosphorylation without cyclin B1 degradation. ANY or CHX promoted this inactivation, which seemed to be more delayed in the physiological activation (IVF). Both inhibitors modulated MPF activity via an ERK1/2-independent pathway, whereas IVF activated the bovine oocytes via an ERK1/2-dependent pathway. Finally, ANY does not activate the JNK and P38 kinase pathways.

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The Role of Adenosine Triphosphate Deficiency in Ethionine-induced Inhibition of Protein Synthesis

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)81133-4 ◽

1963 ◽

Vol 238 (5) ◽

pp. 1757-1763

Author(s):

Saul Villa-Trevino ◽

Kenneth H. Shull ◽

Emmanuel Farber

Keyword(s):

Protein Synthesis ◽

Adenosine Triphosphate ◽

Inhibition Of Protein Synthesis

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Studies on the role of RNA and protein synthesis in the lipolytic action of growth hormone in isolated fat cells

Advances in Enzyme Regulation ◽

10.1016/0065-2571(67)90007-6 ◽

1967 ◽

Vol 5 ◽

pp. 39-51 ◽

Cited By ~ 27

Author(s):

John N. Fain

Keyword(s):

Growth Hormone ◽

Protein Synthesis ◽

Fat Cells ◽

Isolated Fat Cells ◽

Lipolytic Action ◽

Rna And Protein Synthesis

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Recovery of beta-adrenergic receptors following long term exposure of astrocytoma cells to catecholamine. Role of protein synthesis.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)43267-x ◽

1981 ◽

Vol 256 (23) ◽

pp. 12281-12286 ◽

Cited By ~ 4

Author(s):

R.C. Doss ◽

J.P. Perkins ◽

T.K. Harden

Keyword(s):

Protein Synthesis ◽

Adrenergic Receptors ◽

Beta Adrenergic Receptors ◽

Beta Adrenergic ◽

Astrocytoma Cells

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Studies on the Role of Ribosomes in the Regulation of Protein Synthesis in Hypophysectomized and Thyroidectomized Rats

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)96253-8 ◽

1967 ◽

Vol 242 (4) ◽

pp. 650-656

Author(s):

Leonard D. Garren ◽

A.P. Richardson ◽

R. Michael Crocco

Keyword(s):

Protein Synthesis

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Protein Synthesis in Human Leukocytes and Lymphocytes: 1. Effect of Steroids and Sterols

Blood ◽

10.1182/blood.v34.3.348.348 ◽

1969 ◽

Vol 34 (3) ◽

pp. 348-356 ◽

Cited By ~ 18

Author(s):

SEYMOUR WERTHAMER ◽

CARL HICKS ◽

LEONARD AMARAL

Keyword(s):

Protein Synthesis ◽

Steroid Hormones ◽

Plasma Protein ◽

Human Lymphocytes ◽

Amino Acid Incorporation ◽

Binding Factor ◽

In Vitro Effects ◽

Physiologic Role

Abstract The in vitro effects of sterols, cholesterol and 3-methyl cholanthrene and steroids, cortisol, prednisolone and testosterone on protein synthesis in separate popultions of human lymphocytes and leukocytes has been investigated. It has been shown that all agents used result in the inhibition of protein synthesis under these conditions. It has also been shown that the inhibitory mechanism of the steroid hormones requires the presence of plasma, presumably as a protein binding factor in order to achieve its effect. The sterol, cholesterol and 3-methyl cholanthrene, in the absence of plasma, still inhibit amino acid incorporation. However, in the case of cholesterol, the magnitude of inhibition is lower than that observed in the presence of plasma, perhaps indicating a partial plasma dependence. The results presented therefore support the hypothesis that the inhibition of lymphocyte protein synthesis by steroid hormones occurs only when the steroid is bound to a plasma protein. The physiologic role of the plasma protein-cortisol complex and its relation to the condition of lymphopenia in man is discussed.

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