During capacitation in bull spermatozoa, actin and PLC-ζ undergo dynamic interactions

Zygote. 2017 Oct;25(5):558-566. doi: 10.1017/S0967199417000260. Epub 2017 Sep 20.

Abstract

The migration pattern of sperm-specific phospholipase C-ζ (PLC-ζ) was followed and the role of this migration in actin cytoskeleton dynamics was determined. We investigated whether PLC-ζ exits sperm, opening the possibility that PLC-ζ is the 'spermatozoidal activator factor' (SOAF). As capacitation progresses, the highly dynamic actin cytoskeleton bound different proteins to regulate their location and activity. PLC-ζ participation at the start of fertilization was established. In non-capacitated spermatozoa, PLC-ζ is in the perinuclear theca (PT) and in the flagellum, therefore it was decided to determine whether bovine sperm actin interacts with PLC-ζ to direct its relocation as it progresses from non-capacitated (NC) to capacitated (C) and to acrosome-reacted (AR) spermatozoa. PLC-ζ interacted with actin in NC spermatozoa (100%), PLC-ζ levels decreased in C spermatozoa to 32% and in AR spermatozoa to 57% (P < 0.001). The level of actin/PLC-ζ interaction was twice as high in G-actin (P < 0.001) that reflected an increase in affinity. Upon reaching the AR spermatozoa, PLC-ζ was partially released from the cell. It was concluded that actin cytoskeleton dynamics control the migration of PLC-ζ during capacitation and leads to its partial release at AR spermatozoa. It is suggested that liberated PLC-ζ could reach the egg and favour fertilization.

Keywords: Actin; Bull sperm capacitation; PLC-ζ; Protein–protein interaction; SOAF.

MeSH terms

  • Acrosome / metabolism
  • Acrosome / physiology
  • Acrosome Reaction / physiology
  • Actin Cytoskeleton / metabolism
  • Actins / metabolism*
  • Animals
  • Cattle
  • Fertilization / physiology
  • Isoenzymes / metabolism
  • Male
  • Protein Binding
  • Sperm Capacitation / physiology*
  • Sperm Motility / physiology
  • Sperm Tail / metabolism
  • Sperm Tail / physiology
  • Spermatozoa / metabolism
  • Spermatozoa / physiology*
  • Type C Phospholipases / metabolism*

Substances

  • Actins
  • Isoenzymes
  • Type C Phospholipases