Table 2.
Examples of controls of activity of enzymes needed for synthesis of neural gangliosides from ceramide.
| Transport Protein/Enzyme | Factor(s) Affecting Activity | Species * |
|---|---|---|
| CERT (ceramide transporter) | Phosphorylation by protein kinase D  activity [26,27,28] |
Human |
| Glc-cer synthase | Ceramide activity [36] |
Human |
| FAPP2 (four–phosphate adaptor protein 2) | Failure to interact with acyl-coenzyme A binding domain 3 (ACBD3) [37] |
Human |
| Lac-cer synthase (B4GalT5/6) | Sp1 transcription factor synthesis [38] |
Human |
| GM3 synthase (ST3GAL5) | PKC CREB-mediated transcription  GM3 [39] Specificity promotor 1 and activating protein 2 promote expression [40]Enzyme’s cytoplasmic tail determines activity, subcellular localization and stability [41] |
Human Mouse Mouse |
| GD3 synthase (ST8SIA1) | N-glycosylation affects location and activity [42] NF-kB upregulates transcription [43] |
Chicken Human |
| GA2/GM2/GD2 synthase (B4GALNT1) |
During neuronal differentiation [44] Coexistence of multiple isoforms [45]  Sp1 or HDAC1
transcription [46] |
Mouse Hamster Human |
| Sialidase 3 (NEU3) | BDNF its activity [47] |
Rat |
| GA1, GM1a, GD1b, and GT1c synthase (B3GalT4) | Gene hypermethylation expression [48] |
Human |
* Animal sources are indicated as results may be species-dependent. Arrows pointing up indicate an increase, arrows pointing down, a decrease.