Table 1.
Podocyte molecular structure and function
| Structure component | Site | Function |
|---|---|---|
| Podoendin | cell surface protein | unknown |
| Podocalyxin (Pdcx) | Highly charged cell surface protein | electrostatic charge repulsion Pdcx associates with the actin cytoskeleton by its interaction with ezrin and the Na/h exchanger regulatory factor-2 (NHERF-2) |
| Glomerular Epithelial Protein-1 (GLEPP-1) | Podocyte apical cell surface | unknown |
| CD2-associated protein | Basolateral-transmembrane protein | Adaptor protein mediating the connection of slit diaphragm to the actin cytoskeleton |
| Podocin | Basolateral-transmembrane protein | adaptor protein mediating the connection of slit diaphra gm to the actin cytoskeleton |
| Nephrin | slit diaphragm protein | integrity of slit diaphragm and amintenance of normal glomerular permeability |
| P-cadherin (FAT: Fatty Acid Tansporter) | slit diaphragm cadherin | unknown |
| Alpha, beta, gamma catenins | basolateral surface | cell junction-associated proteins |
| Zonula Occludens-1 (ZO-1) | basolateral protein | linker protein for the attachment of slit diaphragm to actin cytoskeleton. Membrane associated guanylate kinase protein |
| Alpha-3-beta1 integrin | basal cell podocyte | interaction between the podocyte and the glomerular basement membrane and maintenance of the integrity of the filtration slit |
| Megalin | cell surface protein | transmembrane receptor of LDL family of receptor |
| Alpha, beta dystroglycan complex | Baso-basolateral cell cell podocyte | Interaction between the podocyte and the glomerular basement membrane and maintance of the integrity of the filtration slit |
| Synaptodin | cytoskeleton | actin-binding protein with unknown function (coordination actin bundling ?) |
| Alpha-actinin 4 | cytoskeleton | isoform of alpha-actinin and an actin-binding protein (actin cross-linking protein) |
| Vascular Endothelial Growth Factor (VEGF) | unknown | signaling molecule expressed by podocyte involved in the formation and maintenance of glomerular capillaries throghout life |
| Wilms Tumor-1 (WT-1) | Unknown inside the nucleus of the body of the podocyte | Zing finger transcription factor and RNA binding protein. Protein of podocyte development |
| 13 A antigen | membrane protein | unknown |
| Actin | Protein filaments in foot processes only | Foot process mobilityand architecture and connected with slit diaphragm, glomerular basement membrane, cell surface foot process (Active regulator of podocyte shape and function) |
| Vimentin | protein filaments and microtubules confined to the podocyte cell body | Cytoskeletal protein |
| Ezrin | Protein linked to actin filaments | unknown. Probably attaches the actin cytoskeleton to podocalyxin via the linker protein NHERF2 (Na/H-exchanger regulatory factor 2) |
| Lmx1b | Unknown inside the nucleus of cell body | protein expressed in podocyte contributes to transcriptional regulation membrane collagen expression by podocytes |
| p21 | unknown | cyclin-dependent kinase (CDK) inhibitor expressed in normal qiuescent podocyte. Inhibits cell podocyte proliferation. |
| p27 | unknown | cyclin-dependent kinase (CDK) inhibitor expressed in normal qiuescent podocyte. Inhibits cell podocyte proliferation. |
| p57 | unknown | cyclin-dependent kinase (CDK) inhibitor expressed in normal qiuescent podocyte. Inhibits cell podocyte proliferation. |