Physiological roles of perinuclear theca and its effects on male infertility

Human and mouse perinuclear theca, their structural features, protein compositions and assembly, physiological roles are summarized． The relationship between perinuclear theca protein-coding gene mutations and human male infertility is discussed． Data from knockout mice suggest that oocyte activation, protection of sperm nucleus, and acrosome-nucleus attachment of sperm are important physiological roles of perinuclear theca． Mutations in PLCZ1 gene are the main genetic cause of oocyte activation failure． Mutations in Ccin gene lead to male infertility due to deformities of sperm heads． Pathogenic variants of Actl7A or Actl9 genes cause sperm acrosome detachment and oocyte activation failure． Future works may focus on the following: novel functions of perinuclear theca, structural biology of ‘inner acrosomal membrane-perinuclear theca-nuclear envelope’ protein complexes, and mutation screening of genes coding for perinuclear theca proteins．