Practice question

Compaction at eight-cell stage transforms loosely associated blastomeres into tightly adherent morula essential for polarization and lineage segregation. This process relies on calcium-dependent homophilic adhesion mediated by E-cadherin coupled via beta-catenin and alpha-catenin to actin cytoskeleton, recruiting to cell-cell contacts upon protein kinase C activation. Cadherin-catenin complex drives cortical tension changes, sealing intercellular gaps and activating polarity proteins Par3/Par6. Functional blocking of E-cadherin prevents compaction and blastocyst formation, demonstrating indispensable mechanical and signaling role of complex during early morphogenesis, epithelialization events critical for development and implantation readiness.