Acrosome reaction in sea urchin

2. Acrosomal Reaction in
Sea Urchin

3. Acrosome reaction
Acrosome reaction is a sum of reactions it
is not a single reaction.
Acrosome is a bag of general protein and
carbohydrate digesting enzymes ,present in
inactive form in head region below sperm
membrane.

4. Steps in acrosome reaction
• Acrosome fusion with
sperm membrane
• Activation of acrosome
vesicle
• Acrosome filament
formation
• Loading of fusogenic
proteins on acrosome
filament

5. Acrosome fusion with sperm membrane
 Second messenger mechanism.
 Calcium channels open .
 Enzymes Activation for fusion.
 Benefit of fusing acrosome membrane with sperm membrane.
 Only one membrane has to be destroyed.
 Less enzymes will use.
 Less damage happen to sperm .

6. Activation of acrosome bag
• Acrosome bag synthesis
• Calcium Ion source and Ion Channels.
• Enzymes for activation of acrosome.
• Acrosomal Activity

8. Formation of acrosome filament
• Calcium dependent .
• These enzymes bind alpha and beta tubulin and convert
actin cluster into acrosomal filament

9. Loading of Fusogenic proteins
• In this step on acrosomal filament fusogenic or bindin
protein are loaded
• For attachment to bindin receptor ,that is present on
specific site on egg membrane of sea urchin.

12. Thank You