Protein kinase C activity in boar sperm

Abstract

SUMMARYMale germ cells undergo different processes within the female reproductive tract to successfully fertilize the oocyte. These processes are triggered by different extracellular stimuli leading to activation of protein phosphorylation. Protein kinase C (PKC) is a key regulatory enzyme in signal transduction mechanisms involved in many cellular processes. Studies in boar sperm demonstrated a role for PKC in the intracellular signaling involved in motility and cellular volume regulation. Experiments using phorbol 12-myristate 13-acetate (PMA) showed increases in the Serine/Threonine phosphorylation of substrates downstream of PKC in boar sperm. In order to gain knowledge about those cellular processes regulated by PKC, we evaluate the effects of PMA on boar sperm motility, lipid organization of plasma membrane, integrity of acrosome membrane and sperm agglutination. Also, we investigate the crosstalk between PKA and PKC intracellular pathways in spermatozoa from this species. The results presented here reveal a participation of PKC in sperm motility regulation and membrane fluidity changes, which is probably associated to acrosome reaction and to agglutination. Also, we show the existence of a hierarchy in the kinases pathway. Previous works on boar sperm suggest a pathway in which PKA is positioned upstream to PKC and this new results support such model.

The compound YK 3-237 promotes pig sperm capacitation-related events

“…Due to the fact that head-to-head sperm agglutination is associated with sperm capacitation (Harayama et al 1998 ; Teijeiro et al 2017 ) and is a pre-requisite for the fertilization of an oocyte to occurs, we studied the effects of YK 3-237 on pig sperm capacitation parameters, such as a rise in the intracellular calcium levels (Ruknudin and Silver 1990 ), increase of p32 tyrosine phosphorylation levels identified as proacrosin binding protein (ACRBP) by Dubé et al ( 2005 ) and as SPACA1 by Macias-Garcia and Gonzalez-Fernandez ( 2023 ), as well as the acrosome reaction (Austin and Bishop 1958 ).…”

Aquaporins Are Essential to Maintain Motility and Membrane Lipid Architecture During Mammalian Sperm Capacitation

“…As the change in pH caused by the blockade of AQPs occurred after the addition of progesterone, it would be reasonable to suggest that sAC activity was unaltered, which would be in agreement with the lack of variations in PKA activity and cAMP levels. A potential candidate to explain the observed alteration in tyrosine phosphorylation levels would be PKC, which is involved in the intracellular signaling pathways that trigger the acrosome reaction ( Teijeiro et al, 2017 ). Therefore, changes in osmoregulation during capacitation could induce latent alterations in sperm function that would become apparent upon triggering the acrosome reaction.…”

Bbs5 functions as the docking compartment of Bbsome binding to Klc3 regulated by Bbs5-Ser246PKC-phosphorylation during mouse spermatogenesis

“…For the time being, there is still no data about the PKC phosphorylation sites of Bbs5. As an important role in various biological processes, PKC also takes part in spermatogenesis [17][18][19]. Bbs5 might be one potential target of which PKC gets involved in since BBS5 is the subunit of BBsome, an indispensable complex during ciliogenesis and spermatogenesis [20,21].…”