Progesterone-induced Acrosome Exocytosis Requires Sequential Involvement of Calcium-independent Phospholipase A2ß (iPLA2ß) and Group X Secreted Phospholipase A2 (sPLA2).
J Biol Chem
; 291(6): 3076-89, 2016 Feb 05.
Article
em En
| MEDLINE
| ID: mdl-26655718
ABSTRACT
Phospholipase A2 (PLA2) activity has been shown to be involved in the sperm acrosome reaction (AR), but the molecular identity of PLA2 isoforms has remained elusive. Here, we have tested the role of two intracellular (iPLA2ß and cytosolic PLA2α) and one secreted (group X) PLA2s in spontaneous and progesterone (P4)-induced AR by using a set of specific inhibitors and knock-out mice. iPLA2ß is critical for spontaneous AR, whereas both iPLA2ß and group X secreted PLA2 are involved in P4-induced AR. Cytosolic PLA2α is dispensable in both types of AR. P4-induced AR spreads over 30 min in the mouse, and kinetic analyses suggest the presence of different sperm subpopulations, using distinct PLA2 pathways to achieve AR. At low P4 concentration (2 µm), sperm undergoing early AR (0-5 min post-P4) rely on iPLA2ß, whereas sperm undergoing late AR (20-30 min post-P4) rely on group X secreted PLA2. Moreover, the role of PLA2s in AR depends on P4 concentration, with the PLA2s being key actors at low physiological P4 concentrations (≤2 µm) but not at higher P4 concentrations (~10 µm).
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Progesterona
/
Acrossomo
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Reação Acrossômica
/
Exocitose
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Fosfolipases A2 do Grupo VI
/
Fosfolipases A2 do Grupo X
Limite:
Animals
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article