Table 1.
Actin-binding proteins involved in oocyte maturation. Known biochemical functions, roles in oocyte maturation and embryogenesis are listed.
| Classes | Proteins | Known biochemical roles | Physiological roles in oocyte maturation |
|---|---|---|---|
| Actin nucleators and NPFs | ARP2/3 complex | Nucleate new actin filaments by branching from existing filaments | Cortical actin cap formation22; Subcortical actin thickening12,13; Generation of cytoplasmic flow to maintain position of spindle in MII oocytes23; Fast-phase migration of spindle65 |
| Formins | Nucleate actin filaments and facilitate filament elongation | Spindle migration27,36; Cytokinesis36; Cytoplasmic actin mesh formation (formin-2)10,11; Meiotic spindle formation (mDia family)45 | |
| Spire | Cooperate with formin-2 and form straight actin filaments | Cytoplasmic actin mesh formation in collaboration with formin-239 | |
| N-WASP | Activate the ARP2/3 complex via cdc42 | Cortical actin cap formation | |
| WAVE2 | Activate the ARP2/3 complex via Rac | Spindle formation and migration66; Subcortical actin formation12 | |
| JMY | Activate the ARP2/3 complex | Spindle formation and migration68 | |
| WHAMM | Activate the ARP2/3 complex | Spindle formation and migraton69 | |
| Filament severing | ADF/cofilin | Sever existing actin filaments and promote recycling of filaments | Recycling of cortical and cytoplasmic actin |
| Filament binding and protection | Tropomyosin(TPM3.1) | Bind actin filaments and protect from depolymerization/modulation of actin-myosin interactions | Maintenance of cortical actin integrity84 |
| Filament capping | Heterodimeric actin-capping protein (CP) | Bind to fast-growing ends of actin filaments and block elongation | Control of cytoplasmic actin mesh in competition with formin-299 |
| Tropomodulin(TMOD3) | Bind slow-growing ends of actin filaments and protect from depolymerization | Maintenance of cytoplasmic actin mesh level |