Table 3.
Substrates, adaptors, and modifiers/regulators of both NEDD4-1 and NEDD4-2.
| Name | Substrate | Adaptor | Modifier/Regulator | Binding Motifs | Modification | Function | Experimental Model Used | References |
|---|---|---|---|---|---|---|---|---|
| ACK-1 (activated Cdc42-associated kinase 1) (NEDD4-1) | 🗸 | PPAY | Monoubiquitination, Polyubiquitination | ACK-1 is a cytoplasmic tyrosine kinase and is a NEDD4-1 and NEDD4-2 substrate. Its degradation through the proteasome results in downregulation of ACK-1. These authors suggest only NEDD4-1 to ubiquitinate ACK-1 | In vitro: COS7, HEK293T, HeLa, T47D, and A549 cells | [151] | ||
| ACK-1 (activated Cdc42-associated kinase 1) (NEDD4-2) | 🗸 | PPAY | Polyubiquitination | Its degradation through the proteasome results in downregulation of ACK-1 although this is contested [151] | In vitro: HeLa and COS7 cells | [152] | ||
| α-synuclein filaments (NEDD4-1) | 🗸 | PDNEAYEMP, PLY, PPLP PPSP, PFY | Monoubiquitination and Polyubiquitination (K63-linked) | Degraded via the lysosome. Potential protection mechanism against Parkinson’s Disease pathogenesis | In vitro: SH-SY5Y In vivo: Drosophila and Rat |
[28,29,30] | ||
| α-synuclein filaments (NEDD4-2) | 🗸 | Polyubiquitination | In vitro: SH-SY5Y cells | [29] | ||||
| AKT (Protein Kinase B) (NEDD4-1) | 🗸 | LPEY, LPFY | Polyubiquitination (K63 and K48-linked) and multi-monoubiquitination | A critical effector kinase that regulates numerous cellular processes such as cell growth, death, differentiation, and migration.NEDD4-1 regulates nuclear trafficking of the activated form of AKT via the proteasome & enhances bortezomib sensitivity | In vitro: MCF-7, HeLa, and NEDD4+/+, and NEDD4−/− cells and MEFs | [153,154] | ||
| AKT (Protein Kinase B) (NEDD4-2) | 🗸 | Inhibitory phosphorylation of NEDD4-2. Inhibits NEDD4-2, increasing ENaC expression and Na+ absorption | In vitro: FRT cells | [155] | ||||
| AMPAR (NEDD4-1) | 🗸 | Ubiquitination | An ionotropic glutamate receptor. Ubiquitination leads to AMPAR internalisation and subsequent degradation | In vivo: Rat dissociated hippocampal or cortical neurons In vitro: HEK293 cells |
[156,157,158] | |||
| AMPAR (NEDD4-2) | 🗸 | Ubiquitination | Ubiquitinates the GRIA1 subunit of AMPAR thereby mediating neuronal excitation | In vivo: Sprague Dawley (SD) rats, Nedd4-2andi and GluA1 knockout mice In vitro: HEK293 cells |
[115,159,160] | |||
| AQP2 (Aquaporin 2) (NEDD4-1) |
🗸 | Polyubiquitination | Ubiquitinates and degrades AQP2 but requires NDFIP1 and NDFIP2 adaptors | In vitro: HEK293 and mpkCCD cells | [161] | |||
| AQP2 (Aquaporin 2) (NEDD4-2) |
🗸 | Polyubiquitination | Ubiquitinates and degrades AQP2 but requires NDFIP1 and NDFIP2 adaptors | In vitro: HEK293 and mpkCCD cells | [161] | |||
| Ca2+ (Calcium ions) (NEDD4-1) | 🗸 | Binds to the C2 domain of NEDD4-1 leading to the activation of its ligase activity and inhibition of auto-regulation. PIP2/IP3 ratio dictates its function in either the proximity of the membrane (PIP2) or cytoplasm (IP3) | Used biophysical techniques to complement the literature (NMR Spectroscopy) | [128] | ||||
| DLG3 Discs Large MAGUK Scaffold Protein 3) (NEDD4-1 and NEDD4-2) | 🗸 | PPGY, PPDY | Monoubiquitination | NEDD4-1 interaction results in Dlg3 monoubiquitination, apical membrane recruitment, and tight junction consolidation | In vitro: MDCK cells In vivo: Co-IP of mouse brain lysates |
[162] | ||
| DVL2 (NEDD4-1 and NEDD4-2) | 🗸 | Ubiquitination | A protein involved in the Wnt pathway. Reported to be ubiquitinated for degradation via NEDD4-1 and NEDD4-2 | In vivo: NEDD4-1fl/fl and NEDD4-2fl/fl mice In vitro: HEK293T, DLD1 and HCT116 cells |
[163] | |||
| ENaC (Epithelial Sodium Channel) (NEDD4-1) | 🗸 | PPNY, PPRY, PPAY | Ubiquitination of α and γ subunits | The epithelial Na+ channel is downregulated through proteosome degradation. Lack of binding motif in Liddle’s syndrome causes hyperactivity | In vitro: rat foetal distal lung epithelial and Xenopus-derived A6 cells Ex vivo: Xenopus oocyte |
[164,165] | ||
| ENaC (Epithelial Sodium Channel) (NEDD4-2) | 🗸 | PPAY, PPNY, PPRY, PPKY | Monoubiquitination | NEDD4-2 catalyses ubiquitination and reduces expression of ENaC at the cell surface through lysosomal degradation. NEDD4-2 also targets Na+/Cl− cotransporter (NCC) in the kidney | In vitro: HEK293T cells | [116,126,166,167] | ||
| Grb10 (Growth Factor Receptor Bound Protein 10) (NEDD4-1) | 🗸 | An adaptor for NEDD4-1 to ubiquitinate and degrade IGF-IR. Required for indirect ubiquitination and degradation of VEGFR2 | In vitro: p6, p6/Grb10, HEK-293 EBNA and HUVEC cells | [42,168,169,170] | ||||
| Grb10 (Growth Factor Receptor Bound Protein 10) (NEDD4-2) | 🗸 | 🗸 | PQTPF | Associates with NEDD4-2 leading to its regulation and inhibition of ubiquitination and degradation of Kv1.3 channels | In vitro: HEK293 cells |
[171] | ||
| LGR5 (Leucine-rich repeat containing G protein-coupled receptor 5) (NEDD4-1 and NEDD4-2) | 🗸 | Ubiquitination | A receptor for R-spondin and is a protein involved in the Wnt pathway. It is apparently degraded via the lysosome and proteasome involving NEDD4-1 and NEDD4-2 | In vivo: NEDD4-1fl/fl and NEDD4-2lfl/fl mice In vitro: HEK293T, DLD1 and HCT116 cells |
[163] | |||
| MTMR4 (NEDD4-1) | 🗸 | PPLY | Ubiquitination | Myotubularin-related protein 4, an inositol phosphatase that regulates endosomal signalling | In vitro: HEK293 or HeLa cells | [172,173] | ||
| MTMR4 (NEDD4-2) | 🗸 | PPLY | MTMR4 reduces NEDD4-2-mediated proteasome degradation of wild type and mutant KCNQ1 and hERG channels via dephosphorylation | In vitro: Induced pluripotent stem cardiomyocytes from human dermal fibroblasts | [174] | |||
| NaV (Voltage-gated Sodium channels)1.2 and 1.7 (NEDD4-1) | 🗸 | PPSY (Proline Proline Serine Tyrosine) | Ubiquitination | Regulates sodium channels through lysosomal degradation | Ex vivo: Xenopus Oocytes | [175] | ||
| Navs (Voltage-gated Sodium channels) 1.2, 1.3,1.5, 1.6, 1.7, 1.8 (NEDD4-2) | 🗸 | PPSY, LPSY | Ubiquitination | NEDD4-2 ubiquitination inhibits activity of multiple Navs, including the cardiac (Nav1.5) and neuronal Navs (Nav1.2, Nav1.7, and Nav1.8) | In vitro: HEK-293 cells. In vivo: SNS-NEDD4-2–/– mice, Pulldown of mouse brain lysates Ex vivo: Xenopus oocytes |
[42,116,122,123,124] | ||
| Ndfip1/2 (NEDD4 family-interacting proteins) (NEDD4-1) | 🗸 | 🗸 | NEDD4 family–interacting protein that activates the HECT domain of NEDD4-1. Ndfip1 binds substrates such as PTEN to act as an adaptor for NEDD4-1 ligase activity | In vitro: HEK-293T, SH-SY5Y, PC3 cells and primary MEFs In vivo: C57BL/6J, Emx1-Cre (C57BL/6) and Nestin-Cre mice (B6.Cg-Tg(Nes-cre)1Kln/J) |
[176] | |||
| Ndfip1/2 (NEDD4 family-interacting proteins) (NEDD4-2 | 🗸 | 🗸 | PPPY, PPSY, LPTY, PSY, PTY | Ndfip activates HECT domain of NEDD4-2 | Ex vivo: Xenopus oocytes | [42,161,176] | ||
| OAT1 (organic anion transporter 1) (NEDD4-1) | 🗸 | Ubiquitination | Organic anion transporter (OAT). NEDD4-1 is an important regulator for hOAT1 ubiquitination, expression, and function via its WW2 and WW3 domains | In vitro: COS-7 and HEK293T cells | [131] | |||
| OAT1/3 (Organic ion transporters 1/3) (NEDD4-2) | 🗸 | Ubiquitination | NEDD4-2 ubiquitination regulates cell surface OAT1/3 expression with their WW3 and WW4 domains | In vitro: COS-7 and HEK293T cells | [131,132] | |||
| PTEN (Phosphatase and tensin homolog) (NEDD4-1& NEDD4-2) | 🗸? | 🗸 | PRR | Multi-monoubiquitinationPolyubiquitination(Ubiquitination independent of NEDD4-1) | PTEN is a tumour suppressor. Nuclear importation occurs via monoubiquitinationNEDD4-1 single and NEDD4-1 & NEDD4-2 double knock out mice do not exhibit stability, subcellular activity or localisation differences of PTEN | In vitro: PC3 and HEK293T cells In vivo: Xenopus tectumIn vivo: Murine |
[111,176,177,178,179,180,181,182] |
?, experimental uncertainty. Further investigation required to confirm result. Abbreviations: PPAY (Proline Proline Alanine Tyrosine), PDNEAYEMP (Proline Aspartate Asparagine Glutamate Alanine Tyrosine Glutamate Methionine Proline), PLY (Proline Leucine Tyrosine), PPLP (Proline Proline Leucine Proline), PPSP (Proline Proline Serine Proline), LPEY (Leucine Proline Glutamate Tyrosine), LPFY (Leucine Proline Phenylalanine Tyrosine), PPGY (Proline Proline Glycine Tyrosine), PPDY (Proline Proline Aspartate Tyrosine), PPNY (Proline Proline Asparagine Tyrosine), PPRY (Proline Proline Arginine Tyrosine), PPAY (Proline Proline Alanine Tyrosine), PPKY (Proline Proline Lysine Tyrosine), PQTPF (Proline Glutamine Threonine Proline Phenylalanine), PPLY (Proline Proline Leucine Tyrosine), PPSY (Proline Proline Serine Tyrosine), LPSY (Leucine Proline Serine Tyrosine), LPTY (Leucine Proline Threonine Tyrosine), PTY (Proline Threonine Tyrosine), PRR (Proline rich region).