info:eu-repo/semantics/article
The early molecular events leading to COFILIN phosphorylation during mouse sperm capacitation are essential for acrosomal exocytosis
Fecha
2022-06Registro en:
Schiavi Ehrenhaus, Liza Jamaica; Romarowski, Ana; Jabloñski, Martina; Krapf, Dario; Luque, Guillermina Maria; et al.; The early molecular events leading to COFILIN phosphorylation during mouse sperm capacitation are essential for acrosomal exocytosis; American Society for Biochemistry and Molecular Biology; Journal of Biological Chemistry (online); 298; 6; 6-2022
0021-9258
CONICET Digital
CONICET
Autor
Schiavi Ehrenhaus, Liza Jamaica
Romarowski, Ana
Jabloñski, Martina
Krapf, Dario
Luque, Guillermina Maria
Buffone, Mariano Gabriel
Resumen
The actin cytoskeleton reorganization during sperm capacitation is essential for the occurrence of acrosomal exocytosis (AR) in several mammalian species. Here, we demonstrate that in mouse sperm, within the first minutes of exposure upon capacitating conditions, the activity of RHOA/C and RAC1 is essential for LIMK1 and COFILIN phosphorylation. However, we observed that the signaling pathway involving RAC1 and PAK4 is the main player in controlling actin polymerization in the sperm head necessary for the occurrence of AR. Moreover, we show that the transient phosphorylation of COFILIN is also influenced by the Slingshot family of protein phosphatases (SSH1). The activity of SSH1 is regulated by the dual action of two pathways. On one hand, RHOA/C and RAC1 activity promotes SSH1 phosphorylation (inactivation). On the other hand, the activating dephosphorylation is driven by okadaic acid-sensitive phosphatases. This regulatory mechanism is independent of the commonly observed activating mechanisms involving PP2B and emerges as a new finely tuned modulation that is, so far, exclusively observed in mouse sperm. However, persistent phosphorylation of COFILIN by SSH1 inhibition or okadaic acid did not altered actin polymerization and the AR. Altogether, our results highlight the role of small GTPases in modulating actin dynamics required for AR.