Antibody against the actin-binding protein depactin attenuates Ca2+ signaling in starfish eggs

Area of Science:

• Cell Biology
• Developmental Biology
• Biochemistry

Background:

• Depactin, an actin-depolymerizing factor (ADF) family protein, severs actin filaments in starfish oocytes.
• Previous studies showed exogenous cofilin augments Ca(2+) release, suggesting actin cytoskeleton modulation of intracellular Ca(2+) signaling.

Purpose of the Study:

• To investigate the role of endogenous depactin in starfish oocytes and eggs.
• To determine the impact of targeting depactin on meiotic progression, Ca(2+) signaling, and fertilization.

Main Methods:

• Microinjection of an anti-depactin antibody into starfish oocytes and eggs.
• Observation of effects on actin cytoskeleton structure, meiotic progression, Ca(2+) response, fertilization envelope elevation, and polyspermy.

Main Results:

• Anti-depactin antibody microinjection altered actin cytoskeleton structure and delayed 1-methyladenine-induced meiotic progression.
• Microinjected antibody reduced Ca(2+) response amplitude in a dose-dependent manner.
• Eggs microinjected with the antibody showed reduced fertilization envelope elevation and increased polyspermy.

Conclusions:

• The actin cytoskeleton plays a role in meiotic maturation and intracellular Ca(2+) signaling in starfish.
• Depactin and the actin cytoskeleton are involved in regulating gamete interaction and cortical granule exocytosis.
• Targeting depactin provides insights into the functional interplay between the actin cytoskeleton and cellular processes during fertilization.