Table 1.
Intracellular and extracellular S100A6 ligands.
| Ligand | Target Region | Direct Effect | Proposed Function | Reference |
|---|---|---|---|---|
| Actin and tropomyosin | ND | ND | Regulation of actin filament dynamics | [48,57] |
| Caldesmon | C-terminus | Decrease in caldesmon affinity to actin and heavy meromyosin (HMM) |
Regulation of caldesmon function in smooth muscle contraction | [49,50,51,52,53] |
| Calponin | ND | Stabilization of calponin | Regulation of calponin function in smooth muscle contraction | [54,55] |
| Coffilin | ND | Decrease in actin depolymerization | Regulation of actin polymerization | [58] |
| Non-muscle myosin IIA | ND | ND | Modulation of cell motility | [56] |
| Tubulin α and β |
ND | ND | Regulation of microtubule organization | [59] |
| Kinesin light chain (KLC) | TPR domain | dissociation of the KLC-JIP1 complex | Modulation of KLC–cargo interaction | [60] |
| FOR20, FOP and OFD1 | N-terminus (aa 1–30) | ND | Modulation of cilia formation | [61] |
| TPPP (tubulin polymerization-promoting protein) | C-terminal region (aa 110–160) | Inhibition of TPPP dimerization | Modulation of microtubule organization | [62] |
| Lamin B1 and A/C | ND | ND | Regulation of chromatin organization | [40,63] |
| Importin α | Armadillo motif; NLS-cargo-binding domain | Inhibition of importin–NPM1 binding | Inhibition of nuclear transport | [66] |
| HMG20A | C-terminus (aa 311–347) | ND | Regulation of neuronal differentiation | [65] |
| RSK1 | ND | ND | Regulation of cell survival and proliferation | [56] |
| Annexins: Anx1, Anx2, Anx6 and Anx11 | N-terminus | ND | Modulation of membrane dynamics | [70,71,72,96] |
| Sgt1 | SGS domain | Inhibition of Sgt1-Hsp90 binding | Modulation of chaperone complexes | [74] |
| CacyBP/SIP | SGS domain | Inhibition of CacyBP/SIP phosphorylation by CKII | Regulation of CacyBP/SIP phosphatase activity and ERK1/2-Elk-1 signaling pathway | [81,82,100] |
| Hop and TOM70 | TPR domain | Dissociation of Hop and TOM70 complexes with Hsp90 or Hsp70 | Modulation of chaperone complexes | [60] |
| Melusin | C-terminus | ND | Regulation of cardioprotective pathway | [76] |
| CHIP | TPR and U-box domains | Moderate inhibition of CHIP interaction with Hsp90 and Hsp70; suppression of mutant p53 degradation | Modulation of chaperone complexes and p53 degradation | [77] |
| Cyp-40 and FKBP52 | TPR domain | Inhibition of Cyp-40 and FKBP52 binding with Hsp90 | Modulation of chaperone complexes | [79] |
| FKBP38 | TPR domain | Dissociation of the FKBP38-Hsp90 and FKBP38-Bcl2 complexes; suppression of Bcl2 stability | Modulation of chaperone complexes | [78] |
| PP5 | TPR domain | Dissociation of the PP5-Hsp90 complex; stimulation of PP5 activity | Modulation of chaperone complexes | [80] |
| P53, p63 and p73 | P53: C-terminal tetramerization domain (aa 293–393); N-terminal transactivation domain (aa 1–57) | Inhibition of p53 tetramerization | Regulation of p53, p63 and p73 oligomerization and activity | [83,84,87] |
| Mdm2 | N-terminus (aa 2–125) | ND | Moderate inhibition of p53 ubiquitination | [86] |
| RAGE | V, C1 and C2 domains | Induction of RAGE dimerization/clustering | Modulation of signal transduction through RAGE | [89,90,120] |
| Integrin β1 | Extracellular domain | Increase in FAK and PAK phosphorylation | Modulation of integrin- dependent signaling | [59] |
| NCX1 and TRPM4 | ND | ND | Modulation of ion transport | [56] |
| Erythropoietin | N- and C- terminus | ND | Regulation of erythropoietin secretion and/or activity | [92] |
| Cytokines, e.g., IFN-β, IL-11 and CNTF | ND | No effect on IFN-β-induced cytotoxicity | Modulation of cytokine activity/signaling | [91,93] |
| Lysozyme | N-terminus | Inhibition of S100A6-RAGE interaction | Modulation of RAGE-dependent signaling | [55,95] |
| Lumican, PRELP and IGFBP-1 | ND | Competition of the IGF-1–IGFBP-1 interaction | Remodeling of extracellular matrix | [94] |
| GAPDH | ND | ND | Regulation of metabolic processes | [96] |
TPR—tetratricopeptide; SGS—SGT1 specific, ND—not determined.