Table 1 Proteins localized at the sperm release boundary
From: Tubulobulbar complex: Cytoskeletal remodeling to release spermatozoa
PROTEIN NAME | FUNCTON | REFERENCE |
|---|---|---|
Arp3 | Formation of branched actin network in TBCs | D’Souza et al.[38] |
Actin-binding proteins | ||
Espin | Actin bundling | Guttmann et al.[24] Young et al.[10] |
Vinculin | Actin cross-linking | |
Cortactin | Actin depolymerization: increases actin turnover in TBCs | Young et al.[10] |
Cofilin | Arp2/3 complex activation | Guttmann et al.[12] |
Eps8 | Actin capping; regulation of bundling and Rac-GTPase: formation of actin bundles and network | Lie et al.[31] |
Paxillin | Turnover of actin network | Mulholland et al.[23] |
N-WASP | Arp2/3 complex activation | Young et al.[10] |
Profilin IV | Assembly–disassembly of F-actin, presumably present at tubulobulbar extensions of Sertoli cells | Obermann et al.[39] |
Adhesion molecules | ||
α6 β1-integrin | Complex associated with disengagement during spermiation | Beardsley et al.[40] |
Nectin 2 | Expressed only in Sertoli cells and stabilizes association of TBC–Sertoli cell adherens complex | |
Nectin 3 | Associated with actin and espin, forms a hetero-trans dimer with nectin 2 | |
Afadin | Nectin–actin linker protein | Guttmann et al.[24] |
Endocytosis | ||
Clathrin | Forms a layer around endocytic vesicles forming clathrin-coated pits | Young et al.[10] |
Amphiphysin 1 | Co-operates with dynamin 1 in clathrin-mediated endocytosis; also involved in actin dynamics | Kusumi et al.[28] |
Dynamin 2 | Pinching off vesicles from the parent membrane and formation of tubular protrusions | Kusumi et al.[28] |
Dynamin 3 | Vaid et al.[16] | |
Early endosomal antigen (EEA) | Marker for early endosomes, linked to internalization–degradation pathway of TBCs | Young et al.[24] |