Table 1. Potential functional consequences of SUMOylation in Ca2+ signalling.
| Target (direct or indirect) | SUMO isoform | Modified lysine | Mechanism or Ca2+ channel type | Proposed SUMOylation effect | Reference |
|---|---|---|---|---|---|
| CaV2.1 subunit (indirect) | SUMO-1 | Unknown | Inhibition of P/Q-type Ca2+ channels | Role in SCA6 pathogenesis | [124] |
| CAMKII (indirect) | SUMO-1 | Unknown | – | Differentiation of Drosophila’s nervous system | [141] |
| CRMP2 (direct) | SUMO-1 SUMO-2/3 | K374 | Inhibition of N-type Ca2+ channels | Reduces Ca2+ influx in sensory neurons | [128] |
| MEF2 (direct) | SUMO-1 | K403 | – | Promotes dendritic claw differentiation | [145,147] |
| NCX3 (direct) | SUMO-1 | K590 | – | Inhibits NCX3 degradation | [85] |
| NFAT (indirect) | SUMO-2 | Unknown | – | Activates pro-hypertrophic genes | [173] |
| RIM1α (direct) | SUMO-1 | K502 | Increase in P/Q-type Ca2+ channel activity | Promotes synaptic vesicles release | [133] |
| SERCA2a (direct) | SUMO-1 | K480 and K585 | – | Increases Ca2+reuptake to sarcoendoplasmic reticulum | [156,177] |
| Synapsin Ia (direct) | SUMO-1 | K687 | – | Sets up releasable synaptic vesicles | [138] |
| Synaptotagmin-1 (indirect) | SUMO-1 | Unknown | – | Impairs neurotransmitter release | [139] |
| Syntaxin 1A (direct) | SUMO-1 | K252, K253 or K256 | – | Increases vesicular endocytosis | [137] |
Abbreviations: CAMKII, Ca2+/calmodulin-dependent protein kinase II; CRMP2, collapsin response mediator protein 2; MEF2, myocyte enhancer factor 2; NCX3, isoform 3 of the Na+/Ca2+ exchanger; NFAT, N-terminal serine residues of the nuclear factor of activated T-cells; RIM1α, Rab3a-interacting molecule 1α; SERCA2a, isoform 2a of sarcoendoplasmic reticulum Ca2+ ATPase.