Protein kinase C isoforms undergo quantitative variations during rat spermatogenesis and are selectively retained at specific spermatozoon sites

Nicoletta Zini, Alessandro Matteucci, Patrizia Sabatelli, Aurelio Valmori, Elisabetta Caramelli, Nadir M. Maraldi

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Signal transduction elements, including protein kinase C, have been identified in mammalian spermatozoa. In order to evaluate the pattern of expression and the subcellular localization of nine different protein kinase C isoforms in the course of spermatogenesis, we utilized quantitative electron microscopy immunocytochemistry on thin sections of rat seminiferous tubules. The results indicate a progressive reduction of the protein kinase C isoforms present in the early stages of spermatogenesis, so that in late spermatids none of them is present in the nucleus, while the isoforms α, γ and β(II) are specifically retained in the acrosome, the isoforms β(I) and ζ in the neck, and the isoform ε in the tail. These isoforms, except for β(II), are maintained at the same sites in spermatozoa. Western blotting analysis indicates the presence of α and γ isoforms in the head subfraction, and of β(I), ζ and ε isoforms in the tail subfraction of spermatozoa. These findings suggest that specific protein kinase C isoforms may be functionally involved in some events of spermatozoa differentiation and, eventually, in the fertilization process.

Original languageEnglish
Pages (from-to)142-150
Number of pages9
JournalEuropean Journal of Cell Biology
Issue number2
Publication statusPublished - 1997



  • Immunocytochemistry
  • Protein kinase C
  • Signal transduction
  • Spermatogenesis
  • Spermatozoa

ASJC Scopus subject areas

  • Anatomy
  • Cell Biology

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