Structural characterizations of human periostin dimerization and cysteinylation

Area of Science:

• Biochemistry
• Structural Biology
• Extracellular Matrix Research

Background:

• Human periostin is crucial for extracellular matrix remodeling through heterophilic and homophilic interactions.
• The structural basis for periostin's extensive protein interactions remained unclear.
• Understanding these interactions is vital for comprehending physiological and pathological processes.

Discussion:

• Crystal structures of human periostin (EMI-Fas1^I-IV) and a Cys60Ala mutant were determined.
• Multi-angle light scattering and biochemical assays confirmed periostin predominantly exists as a dimer in solution.
• The EMI domain is identified as the primary mediator of periostin's homophilic interactions.

Key Insights:

• Periostin forms dimers, with the EMI domain driving homophilic binding.
• Cysteinylation at Cys60 was confirmed via mass spectrometry but minimally impacts homophilic interaction.
• Structural data provides a foundation for understanding periostin's heterophilic interactions with other proteins.

Outlook:

• Further investigation into the structural mechanisms of heterophilic interactions.
• Exploring the implications of periostin's dimeric structure in various biological contexts.
• Potential therapeutic strategies targeting periostin interactions in disease.