PP1γ1 is unable to substitute for the mammal-specific PP1γ2 isoform to support male fertility and sperm function.

In Brief: Protein phosphatase 1 catalytic subunit gamma isoform 2 (PP1γ2) is a unique phosphatase expressed only in mammalian testes and sperm cells. The PP1γ2 isoform is indispensable for sperm motility and fertility and cannot be replaced by the PP1γ1 isoform for these functions.

Abstract: The serine-threonine phosphatase has four paralogs - PP1α, PP1β, PP1γ1 and PP1γ2 - encoded by three genes, Ppp1ca, Ppp1cb and Ppp1cc.

The protein YWHAE (14-3-3 epsilon) in spermatozoa is essential for male fertility.

Background: Spermatogenesis is a complex biological process highlighted by synthesis and activation of proteins that regulate meiosis and cellular differentiation occur during spermatogenesis. 14-3-3 proteins are adaptor proteins that play critical roles in kinase signaling, especially for regulation of cell cycle and apoptosis in eukaryotic cells. There are seven isoforms of the 14-3-3 family proteins encoded by seven genes (β, ε, γ, η, θ/τ, ζ and σ).