Isoforms of myosin and actin in human, monkey and rat myometrium

Comparison of pregnant and non-pregnant uterus proteins

Authors

  • Françoise CAVAILLÉ,

    Corresponding author
    1. Institut National de la Santé et de la Recherche Médicale, Unité 262, Clinique Universitaire Baudelocque, Paris
      Correspondence to Françoise Cavaillé, Unité 262 de l'INSERM, Clinique Universitaire Baudelocque, 123 Boulevard de Port-Royal, F-75674 Paris Cedex 14, France
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  • Chantal JANMOT,

    1. Laboratoire de Biologie Physicochimique, Centre National de la Recherche Scientifique Unité Associée 1131, Université Paris-Sud, Orsay
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  • Sylvie ROPERT,

    1. Institut National de la Santé et de la Recherche Médicale, Unité 262, Clinique Universitaire Baudelocque, Paris
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  • Anne d'ALBIS

    1. Laboratoire de Biologie Physicochimique, Centre National de la Recherche Scientifique Unité Associée 1131, Université Paris-Sud, Orsay
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Correspondence to Françoise Cavaillé, Unité 262 de l'INSERM, Clinique Universitaire Baudelocque, 123 Boulevard de Port-Royal, F-75674 Paris Cedex 14, France

Abstract

Using several electrophoretic procedures, we have compared the forms of myosin and actin in pregnant and non-pregnant uterus of woman, monkey (Macaca fascicularis) and rat. On non-dissociating gels, native myosin of the three species migrates as a single band, of identical mobility independently of the physiological state. Remigration of this band in dissociating conditions shows that it is constituted of two heavy chains of respectively 201 kDa and 205 kDa; the relative proportions of these two bands are different for the three animal species but do not vary during pregnancy. Using two-dimensional gel electrophoresis, we found that the 17-kDa light chain of purified uterus myosin exists under two isoelectric forms, the more acidic one becoming progressively predominant at the end of pregnancy in the human as in the monkey uterus, while we observed no changes in the rat. In two-dimensional gel electrophoresis, actin of human, monkey and rat uterus is present under three isoforms, the most basic one (the γ form) increasing early in pregnancy in the two primate species but being always the most abundant form in the rat. The ATPase activity of human uterus myosin was found to be similar for the protein extracted from both pregnant and non-pregnant uterus. The changes observed in the 17-kDa light chain and in the actin isoforms might nevertheless participate in the modifications of contractility of the uterus during pregnancy of the primates.

Abbreviations
LC

myosin light chain

HC

myosin heavy chain

SDS

sodium dodecyl sulphate

Enzyme
 

(IUB Recommendations 1984). Myosin ATPase (EC 3.6.1.32)

Ancillary

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