Carbohydrate self-recognition mediates marine sponge cellular adhesion

Area of Science:

• Marine biology
• Cellular biology
• Biochemistry

Background:

• Sponges (Porifera) are early multicellular organisms crucial for studying cell recognition.
• Cellular adhesion in sponges involves proteoglycan-like aggregation factors (AFs).
• Calcium-dependent AF self-association is a key adhesion event, potentially involving carbohydrate self-recognition.

Purpose of the Study:

• To investigate the role of specific carbohydrate epitopes in the calcium-dependent cellular adhesion of the sponge Microciona prolifera.
• To elucidate the mechanism of carbohydrate self-recognition in sponge cell adhesion.

Main Methods:

• Designed a surface plasmon resonance detection system to mimic carbohydrate involvement in M. prolifera cellular adhesion.
• Analyzed the self-association of specific carbohydrate epitopes, including a sulfated disaccharide and a pyruvylated trisaccharide.
• Tested the effect of substituting calcium ions with magnesium or manganese ions on carbohydrate interactions.

Main Results:

• Demonstrated that self-recognition of a sulfated disaccharide is a primary driver of calcium-dependent cellular adhesion in M. prolifera.
• Showed that this interaction is specific and not solely based on electrostatic forces, as other sulfated carbohydrates did not self-associate.
• Confirmed that the interaction is dependent on Ca(2+) ions, as it was abolished by substitution with Mg(2+) or Mn(2+) ions.

Conclusions:

• Confirmed the existence of true carbohydrate self-recognition in sponge cellular adhesion.
• Highlighted the significant role of a specific sulfated disaccharide in the calcium-dependent adhesion mechanism.
• Suggested that these findings have implications for understanding carbohydrate roles in cellular recognition across higher organisms.