# Interactome of the oncogenic ΔNp73α isoform in human papillomavirus 38 E6/E7-transformed keratinocytes

Luc Negroni, Valerio Taverniti, Massimo Tommasino, Katia Zanier

► To cite this version:

Luc Negroni, Valerio Taverniti, Massimo Tommasino, Katia Zanier. Interactome of the oncogenic ΔNp73α isoform in human papillomavirus 38 E6/E7-transformed keratinocytes. Microbiology Resource Announcements, 2025, 14 (4), pp.e01071-24. 10.1128/mra.01071-24. hal-05404038

HAL Id: hal-05404038

https://hal.science/hal-05404038v1

Submitted on 8 Dec 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Interactome of the oncogenic ΔNp73α isoform in human papillomavirus 38 E6/E7-transformed keratinocytes

Luc Negroni,¹ Valerio Taverniti,² Massimo Tommasino,² Katia Zanier³

**AUTHOR AFFILIATIONS** See affiliation list on p. 6.

**ABSTRACT** ΔNp73α is a major oncogenic isoform of tumor suppressor p73. Here, we report ΔNp73α protein-binding partners in the organelle and cytoplasmic compartments of a cellular model consisting of human keratinocytes transformed by the E6 and E7 oncoproteins of the β-HPV38 virus associated with non-melanoma skin cancer.

**KEYWORDS** p53, deltaNp73, oncogenic viruses, HPV, interactome, AP-MS, cancer, proteomics, mass-spectrometry

The tumor suppressor p53 family comprises three transcription factors (TFs), p53, p63, and p73, which, despite sharing high sequence identity, display specific functions and regulation. All three TFs are enriched in the nucleus, where they act on transcription and DNA repair, whereas their levels are regulated in the cytoplasm by ubiquitin-dependent or ubiquitin-independent degradation. In addition, mitochondrial localization has been reported for p53 and p73 (1). The genes coding for the three proteins (TP53, TP63, and TP73) can also be expressed as multiple isoforms (2). The highly carcinogenic ΔNp73α isoform investigated here is a dominant-negative inhibitor of full-length p53 and p73 (TAp53 and TAp73α) (3). It is generated by transcription from the internal P2 promoter of TP73 and, consequently, lacks the N-terminal transactivation domain (2, 4, 5). Expression of viral oncoproteins can also result in ΔNp73α accumulation (6, 7), including the E6 and E7 oncoproteins from cutaneous beta (β) human papillomavirus (HPV) types (8–10) associated with non-melanoma skin cancer (11).

We have performed affinity purification-mass spectrometry (AP-MS) to characterize the ΔNp73α interactome using human keratinocytes immortalized by the β-HPV38 E6 and E7 oncoproteins as a model of cellular transformation (named 38HK hereafter) (8). To this end, we generated two stable cell lines, expressing either ΔNp73α fused to the N-terminus of the tandem affinity purification (TAP) tag (ΔNp73α-TAP) or TAP alone (negative control) (12). To discriminate between cytoplasmic versus nuclear or other organelle interactants, 38HK ΔNp73α-TAP and TAP 38HK cells were fractionated as described in our previous report (12). Briefly, 38HK cells were lysed mechanically in hypotonic buffer and centrifuged. The supernatant, corresponding to the cytoplasmic extract, was recovered. The pellet, containing nuclei and other organelles, was resuspended in buffer containing NaCl (250 mM) and glycerol (20%), incubated on ice, and centrifuged. The supernatant from this second centrifugation corresponds to the nuclear/organelle extract. Then, extracts were processed by tandem affinity purification (13) following the protocol described in Reference (12). Protein complexes were eluted from calmodulin beads and analyzed by SDS-PAGE and Western blotting or silver staining. Protein levels were quantified by the Bradford assay.

Eluates from calmodulin beads were precipitated with trichloroacetic acid, and the pellet was washed with acetone and dissolved with 2 M urea. Samples were digested with 100 ng of trypsin at 37°C for 10 h. The resulting peptide mixtures were directly analyzed by MS with a nanoLC U3000 in-line coupled with an Orbitrap Elite mass

**Editor** Jennifer Geddes-McAlister, University of Guelph, Guelph, Ontario, Canada

Address correspondence to Katia Zanier, zanier@unistra.fr.

Author Massimo Tommasino passed away during the preparation of this manuscript.

The authors declare no conflict of interest.

See the funding table on p. 6.

See the companion article at https://doi.org/10.1128/msphere.00056-23.

Received 2 October 2024

Accepted 7 February 2025

Published 26 March 2025

Copyright © 2025 Negroni et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
<table><caption>TABLE 1 Top interactants of ΔNp73α (Log2 FC >2.1)ab</caption><thead><tr><th>Log2 (FC)</th><th>-Log (P-value)</th><th>Accession</th><th>Gene name</th><th>Log2 (FC)</th><th>-Log (P-value)</th><th>Accession</th><th>Gene name</th></tr></thead><tbody><tr><td>6.93</td><td>3.77</td><td>P09525</td><td>ANXA4</td><td>2.42</td><td>1.66</td><td>Q14257</td><td>RCN2</td></tr><tr><td><strong>6.4</strong></td><td><strong>5.92</strong></td><td><strong>O15350</strong></td><td><strong>ΔNp73α</strong></td><td>2.4</td><td>3.87</td><td>P28715</td><td>ERCC5</td></tr><tr><td>6.09</td><td>4.02</td><td>Q9H3D4</td><td>TP63</td><td>2.38</td><td>2.13</td><td>Q96IZ0</td><td>PAWR</td></tr><tr><td>5.26</td><td>2.51</td><td>P33121</td><td>ACSL1</td><td>2.38</td><td>2.35</td><td>Q13470</td><td>TNK1</td></tr><tr><td>4.97</td><td>4.06</td><td>P33121</td><td>MRPS22</td><td>2.33</td><td>1.36</td><td>P67775</td><td>PPP2CA</td></tr><tr><td>4.66</td><td>3.05</td><td>O95232</td><td>LUC7L3</td><td>2.33</td><td>1.68</td><td>Q8N985</td><td>JMY</td></tr><tr><td>4.58</td><td>4.48</td><td>P82673</td><td>MRPS35</td><td>2.32</td><td>1.31</td><td>Q9UI12</td><td>ATP6V1H</td></tr><tr><td>4.37</td><td>2.38</td><td>P50995</td><td>ANXA11</td><td>2.32</td><td>0.79</td><td>Q96RN5</td><td>MED15</td></tr><tr><td>4.03</td><td>1.98</td><td>Q92665</td><td>MRPS31</td><td>2.31</td><td>3.74</td><td>Q13573</td><td>SNW1</td></tr><tr><td>3.99</td><td>2.19</td><td>Q9Y2R5</td><td>MRPS17</td><td>2.3</td><td>3.34</td><td>O94915</td><td>FRYL</td></tr><tr><td>3.87</td><td>2.46</td><td>P27540</td><td>ARNT</td><td>2.3</td><td>1.4</td><td>Q9UHI6</td><td>DDX20</td></tr><tr><td>3.82</td><td>2.47</td><td>Q12965</td><td>MYO1E</td><td>2.28</td><td>5.03</td><td>Q6UB35</td><td>MTHFD1L</td></tr><tr><td>3.82</td><td>2.95</td><td>Q9Y3D9</td><td>MRPS23</td><td>2.28</td><td>1.78</td><td>Q14241</td><td>ELOA</td></tr><tr><td>3.8</td><td>3.74</td><td>O95425</td><td>SVIL</td><td>2.28</td><td>2.61</td><td>Q9UPN3</td><td>MACF1</td></tr><tr><td>3.78</td><td>2.51</td><td>O60828</td><td>PQBP1</td><td>2.27</td><td>1.36</td><td>Q00443</td><td>PIK3C2A</td></tr><tr><td>3.77</td><td>1.22</td><td>Q96A65</td><td>EXOC4</td><td>2.26</td><td>4.77</td><td>P19013</td><td>KRT4</td></tr><tr><td>3.74</td><td>4.06</td><td>Q92552</td><td>MRPS27</td><td>2.26</td><td>1.2</td><td>Q58WW2</td><td>DCAF6</td></tr><tr><td>3.7</td><td>2.14</td><td>O8IY21</td><td>DDX60</td><td>2.26</td><td>2.54</td><td>O15460</td><td>P4HA2</td></tr><tr><td>3.57</td><td>3.61</td><td>P82933</td><td>MRPS9</td><td>2.26</td><td>1.46</td><td>P82932</td><td>MRPS6</td></tr><tr><td>3.57</td><td>3.3</td><td>Q460N5</td><td>PARP14</td><td>2.25</td><td>1.47</td><td>Q9GZL7</td><td>WDR12</td></tr><tr><td>3.56</td><td>3.81</td><td>O43166</td><td>SIPA1L1</td><td>2.24</td><td>1.47</td><td>Q99959</td><td>PKP2</td></tr><tr><td>3.5</td><td>1.42</td><td>Q709C8</td><td>VP513C</td><td>2.24</td><td>3.03</td><td>Q15427</td><td>SF3B4</td></tr><tr><td>3.41</td><td>1.67</td><td>Q9NP97</td><td>DYNLRB1</td><td>2.23</td><td>1.65</td><td>O43837</td><td>IDH3B</td></tr><tr><td>3.35</td><td>2.6</td><td>P62841</td><td>RPS15</td><td>2.22</td><td>1.7</td><td>Q9BU76</td><td>MMTAG2</td></tr><tr><td>3.27</td><td>2.32</td><td>O60573</td><td>EIF4E2</td><td>2.21</td><td>1.88</td><td>P56182</td><td>RRP1</td></tr><tr><td>3.22</td><td>3.45</td><td>Q9NYL9</td><td>TMOD3</td><td>2.21</td><td>3.37</td><td>Q96SU4</td><td>OSBPL9</td></tr><tr><td>3.22</td><td>1.61</td><td>Q9H788</td><td>SH2D4A</td><td>2.19</td><td>2.76</td><td>Q9UID3</td><td>VPSS1</td></tr><tr><td>3.21</td><td>2.64</td><td>P82675</td><td>MRPS5</td><td>2.19</td><td>3.26</td><td>O75962</td><td>TRIO</td></tr><tr><td>3.14</td><td>2.31</td><td>OQ7002</td><td>CDK18</td><td>2.19</td><td>3.77</td><td>Q5VSL9</td><td>STRIP1</td></tr><tr><td>3.14</td><td>2.55</td><td>O75676</td><td>RP56KA4</td><td>2.19</td><td>2.22</td><td>Q8IXW5</td><td>RPAP2</td></tr><tr><td>3.12</td><td>3.12</td><td>P08758</td><td>ANXA5</td><td>2.18</td><td>4.65</td><td>Q86Y56</td><td>DNAAF5</td></tr><tr><td>3.12</td><td>3.72</td><td>Q9C037</td><td>TRIM4</td><td>2.18</td><td>3.88</td><td>Q96ED9</td><td>HOOK2</td></tr><tr><td>3.06</td><td>2.35</td><td>Q9BQS8</td><td>FYCO1</td><td>2.17</td><td>1.4</td><td>Q13144</td><td>EIF2B5</td></tr><tr><td>3.05</td><td>2.89</td><td>Q9BSJ2</td><td>TUBGCP2</td><td>2.16</td><td>1.67</td><td>Q99683</td><td>MAP3K5</td></tr><tr><td>3.04</td><td>1.53</td><td>A6NKD9</td><td>CCDC85C</td><td>2.12</td><td>1.78</td><td>Q15345</td><td>LRRC41</td></tr><tr><td>2.95</td><td>1.15</td><td>Q9Y3D3</td><td>MRPS16</td><td>2.11</td><td>3.81</td><td>Q14012</td><td>CAMK1</td></tr></tbody></table>

(Continued on next page)
<table><caption>TABLE 1 Top interactants of ΔNp73a (Log2 FC >2.1)ab (Continued)</caption><thead><tr><th>Log2 (FC)</th><th>-Log (P-value)</th><th>Accession</th><th>Gene name</th><th>Log2 (FC)</th><th>-Log (P-value)</th><th>Accession</th><th>Gene name</th></tr></thead><tbody><tr><td>2.93</td><td>3.73</td><td>O00743</td><td>PPP6C</td><td>2.1</td><td>1.92</td><td>Q9NQG5</td><td>RPRD1B</td></tr><tr><td>2.89</td><td>5.13</td><td>P58107</td><td>EPPK1</td><td>2.1</td><td>2.29</td><td>Q15746</td><td>MYLK</td></tr><tr><td>2.88</td><td>1.46</td><td>P49841</td><td>GSK3B</td><td>2.1</td><td>1.83</td><td>P43686</td><td>PSMC4</td></tr><tr><td>2.87</td><td>2.04</td><td>Q6YN16</td><td>HSDL2</td><td></td><td></td><td></td><td></td></tr><tr><td>2.87</td><td>1.36</td><td>Q7RTP6</td><td>MICAL3</td><td>9.3</td><td>6.53</td><td>O15350</td><td>ΔNp73a</td></tr><tr><td>2.85</td><td>1.73</td><td>P55084</td><td>HADHB</td><td>8.8</td><td>3.45</td><td>Q9H3D4</td><td>TP63</td></tr><tr><td>2.84</td><td>1.56</td><td>Q15628</td><td>TRADD</td><td>4.31</td><td>3.12</td><td>O95816</td><td>BAG2</td></tr><tr><td>2.83</td><td>2.27</td><td>P35244</td><td>RPA3</td><td>4.22</td><td>3.05</td><td>P14735</td><td>IDE</td></tr><tr><td>2.8</td><td>1.12</td><td>O95639</td><td>CPSF4</td><td>4.18</td><td>2.47</td><td>Q9H4H8</td><td>FAM83D</td></tr><tr><td>2.8</td><td>1.75</td><td>P15735</td><td>PHKG2</td><td>4</td><td>3.29</td><td>O95232</td><td>LUC7L3</td></tr><tr><td>2.79</td><td>2.86</td><td>P82930</td><td>MRRPS34</td><td>3.66</td><td>2.6</td><td>Q53RT3</td><td>ASPRV1</td></tr><tr><td>2.78</td><td>4.02</td><td>Q9BY89</td><td>KIAA1671</td><td>3.51</td><td>2.49</td><td>P33121</td><td>ACSL1</td></tr><tr><td>2.77</td><td>3.34</td><td>Q8N5S9</td><td>CAMKK1</td><td>3.49</td><td>3.67</td><td>Q9Y285</td><td>FAR5A</td></tr><tr><td>2.75</td><td>2.12</td><td>Q13395</td><td>TARBPI</td><td>3.45</td><td>1.94</td><td>O14579</td><td>COPE</td></tr><tr><td>2.74</td><td>2.43</td><td>P51398</td><td>DAP3</td><td>3.19</td><td>3.75</td><td>Q7Z4S6</td><td>KIF21A</td></tr><tr><td>2.73</td><td>2.05</td><td>O43615</td><td>TIMM44</td><td>3.11</td><td>2.48</td><td>P01036</td><td>CST4</td></tr><tr><td>2.73</td><td>1.77</td><td>Q9UHR6</td><td>ZNHIT2</td><td>3.09</td><td>4</td><td>P53618</td><td>COPB1</td></tr><tr><td>2.69</td><td>2.26</td><td>Q15404</td><td>RSU1</td><td>2.82</td><td>3.01</td><td>Q8IVH4</td><td>MMAA</td></tr><tr><td>2.69</td><td>3.09</td><td>P30038</td><td>ALDH4A1</td><td>2.77</td><td>1.68</td><td>O13200</td><td>PSMD2</td></tr><tr><td>2.69</td><td>2.04</td><td>Q9UG63</td><td>ABCF2</td><td>2.65</td><td>2.18</td><td>P12273</td><td>PIP</td></tr><tr><td>2.69</td><td>4.46</td><td>Q08380</td><td>LGALS3BP</td><td>2.65</td><td>1.48</td><td>P63098</td><td>PPP3R1</td></tr><tr><td>2.69</td><td>4.45</td><td>O15296</td><td>ALOX15B</td><td>2.58</td><td>2.16</td><td>Q6IQ49</td><td>SDE2</td></tr><tr><td>2.67</td><td>1.69</td><td>Q9BV14</td><td>NOC4L</td><td>2.57</td><td>1.72</td><td>P36952</td><td>SERP1N85</td></tr><tr><td>2.65</td><td>0.84</td><td>Q9Y6Q9</td><td>NCOA3</td><td>2.52</td><td>4.98</td><td>Q9BPW8</td><td>NIP5NAP1</td></tr><tr><td>2.64</td><td>1.19</td><td>P49411</td><td>TUFM</td><td>2.47</td><td>2.37</td><td>Q9BYE4</td><td>SPRR2G</td></tr><tr><td>2.64</td><td>1.19</td><td>Q9BQG0</td><td>MYBBP1A</td><td>2.47</td><td>1.86</td><td>O94822</td><td>LTN1</td></tr><tr><td>2.62</td><td>2.09</td><td>Q9UNQ2</td><td>DIMT1</td><td>2.46</td><td>0.98</td><td>Q9C075</td><td>KRT23</td></tr><tr><td>2.61</td><td>2.23</td><td>O95816</td><td>BAG2</td><td>2.42</td><td>2.4</td><td>Q9BRT2</td><td>UQCC2</td></tr><tr><td>2.6</td><td>2.5</td><td>P55209</td><td>NAP1L1</td><td>2.36</td><td>1.96</td><td>P11310</td><td>ACADM</td></tr><tr><td>2.58</td><td>2</td><td>Q99700</td><td>ATXN2</td><td>2.32</td><td>1.86</td><td>Q99961</td><td>SH3GL1</td></tr><tr><td>2.54</td><td>3.44</td><td>Q96II8</td><td>LRCH3</td><td>2.27</td><td>2.18</td><td>P07858</td><td>CTSB</td></tr><tr><td>2.53</td><td>1.51</td><td>Q13613</td><td>MTMR1</td><td>2.24</td><td>2.86</td><td>P46199</td><td>MTIF2</td></tr><tr><td>2.52</td><td>0.81</td><td>P46019</td><td>PHKA2</td><td>2.23</td><td>4.89</td><td>P11142</td><td>HSPA8</td></tr><tr><td>2.51</td><td>1.87</td><td>P78347</td><td>GTF2I</td><td>2.21</td><td>2.38</td><td>P49590</td><td>HARS2</td></tr><tr><td>2.5</td><td>2.08</td><td>Q5TSU3</td><td>ARHGAP21</td><td>2.21</td><td>3.14</td><td>O75323</td><td>NIP5NAP2</td></tr><tr><td>2.47</td><td>1.12</td><td>Q9NRA8</td><td>EIF4ENIF1</td><td>2.18</td><td>2.41</td><td>P58107</td><td>EPPK1</td></tr><tr><td>2.46</td><td>3.36</td><td>Q8WUM0</td><td>NUP133</td><td>2.16</td><td>3.91</td><td>Q15418</td><td>RPS6KA1</td></tr></tbody></table>

(Continued on next page)
<table><caption>TABLE 1 Top interactants of ΔNp73α (Log2 FC > 2.1)ªᵇ (Continued)</caption><thead><tr><th>Log2 (FC)</th><th>-Log (P-value)</th><th>Accession</th><th>Gene name</th><th>Log2 (FC)</th><th>-Log (P-value)</th><th>Accession</th><th>Gene name</th></tr></thead><tbody><tr><td>2.46</td><td>2.57</td><td>Q5GLZ8</td><td>HERC4</td><td></td><td></td><td></td><td></td></tr><tr><td>2.46</td><td>3.09</td><td>Q86X10</td><td>RALGAPB</td><td></td><td></td><td></td><td></td></tr><tr><td>2.43</td><td>2.68</td><td>O43148</td><td>RNMT</td><td></td><td></td><td></td><td></td></tr></tbody></table>

<footnote>ªAll significant interactant at https://doi.org/10.5281/zenodo.14865996.</footnote>

<footnote>ᵇthe ΔNp73α bait is indicated in bold/italics.</footnote>
<figure><img src="image_2.png" /><figcaption>FIG 1 Volcano plot analysis of ΔNp73α partners in the nucleus/organelle (left) and cytoplasm (right) fractions of 38HK cells. The black continuous line indicates the limit of significance (FDR 5%, S0 = 1). Proteins situated on the right-hand side of this line (positive Log₂ value) are significant interactants. These proteins are color coded according to the localization retrieved from the Gene Ontology Resource (https://geneontology.org). Red: nucleus; green: cytoplasm; blue: mitochondria; gray: localization not reported; black: ΔNp73α bait.</figcaption></figure>

spectrometer using a nano-electrospray source (Thermo Scientific). MS measurements were performed on one biological sample per condition. Technical variability was estimated from three MS acquisitions for each sample (technical replicates). Peptides were separated using a C18 column (75 µm × 25 cm) with a 35 min linear gradient from 5% to 50% buffer B (A: 0.1% trifluoroacetic acid in H₂O/B: 80% ACN, 0.08% trifluoroacetic acid in H₂O). The mass spectrometer was operated in data-dependent mode with survey scans from m/z 300–1650 acquired in the Orbitrap at a resolution of 120,000 at m/z 400. Proteins were identified using Proteome Discoverer 2.5 software (Thermo Scientific), with false discovery rate (FDR) < 1% and at least one unique peptide. Label-free quantification was based on eXtracted Ion Chromatography (XIC) using the Minora node from Proteome Discoverer. Precursor and fragment mass tolerance were set at 7 ppm and 0.5 Da, respectively. Oxidation (M) was set as variable modification and carbamidomethylation (C) as fixed modification. The human fasta database with 20,419 sequences was obtained from Uniprot (https://www.uniprot.org/proteomes/UP000005640). Statistical analyses were performed using Perseus 1.6.1.5 according to the processing workflow described by the authors (14). The repeated t-test used for volcano plot analyses was based on standard parameters of Perseus (FDR 5%, S0 = 1).

The lists of the top interactants of ΔNp73α (Log2FC > 2.1) in the nucleus/organ-
elle and cytoplasmic fractions are reported in Table 1. The statistics from Perseus is
presented in a volcano plot with each protein colored according to Gene Ontology
Cellular Component (Fig. 1). The nuclear/organelle and cytoplasmic fractions are strongly
enriched with protein partners with reported nuclear and cytoplasmic localization,
respectively, thereby validating our biochemical approach. While more abundant in the
nuclear/cytoplasmic fractions, mitochondrial binders are also present in the cytoplasmic
fraction.
In our previous study (12), we have characterized the interaction of ΔNp73α with the E2F4/p130 transcriptional repressor complex, which is detected in the nuclear/ organelle fraction of these analyses. Results show that E2F4 binds to ΔNp73α but not to the full-length TAp73α protein, suggesting that the interactomes of the oncogenic isoform and of the tumor suppressor protein may be different.

## ACKNOWLEDGMENTS

The authors would like to thank Bertrand Seraphin (IGBMC, Strasbourg) for providing the TAP vector. The work was supported by funding from IARC-WHO and from the 'Institut National de la Santé et de la Recherche Médicale' (ref. ENV201610) to T.M., and grants from Agence Nationale de la Recherche (ANR JCJC, ref. ANR-13-JSV8-0004-01), 'Fondation pour La Recherche Médicale' (Equipes FRM, ref. DEQ20180339231), and 'Institut National du Cancer' (INCa, ref. PLBIO21-151) to K.Z.

## AUTHOR AFFILIATIONS

¹Proteomics Platform, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)/INSERM U964/CNRS UMR 7104/Université de Strasbourg, Illkirch, France

²International Agency for Research on Cancer (IARC), World Health Organization, Lyon, Auvergne-Rhône-Alpes, France

³Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR 7242), Ecole Supérieure de Biotechnologie de Strasbourg, Illkirch, Grand Est, France

## AUTHOR ORCIDs

Katia Zanier http://orcid.org/0000-0002-7183-7356

## FUNDING

<table><thead><tr><td>Funder</td><td>Grant(s)</td><td>Author(s)</td></tr></thead><tbody><tr><td>Institut National de la Santé et de la Recherche Médicale</td><td>ENV201610</td><td>Massimo Tommasino</td></tr><tr><td>Agence Nationale de la Recherche</td><td>ANR-13-JSV8-0004-01</td><td>Katia Zanier</td></tr><tr><td>Fondation pour la Recherche Médicale</td><td>DEQ20180339231</td><td>Katia Zanier</td></tr><tr><td>Institut National du Cancer</td><td>PLBIO21-151</td><td>Katia Zanier</td></tr></tbody></table>

## AUTHOR CONTRIBUTIONS

Luc Negroni, Formal analysis, Investigation, Methodology, Writing – original draft | Valerio Taverniti, Conceptualization, Investigation | Massimo Tommasino, Conceptualization, Funding acquisition, Project administration, Supervision | Katia Zanier, Conceptualization, Funding acquisition, Project administration, Supervision, Writing – original draft, Writing – review and editing

## DATA AVAILABILITY

The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD056377. Lists of significant interactants (Log2 FC > 1) and relative statistics have been reported on the GitHub/Zenodo repository (https://doi.org/10.5281/zenodo.14865996).

## REFERENCES

1. Sayan AE, Sayan BS, Gogvadze V, Dinsdale D, Nyman U, Hansen TM, Zhivotovsky B, Cohen GM, Knight RA, Melino G. 2008. P73 and caspase-cleaved p73 fragments localize to mitochondria and augment TRAIL-induced apoptosis. Oncogene 27:4363-4372. https://doi.org/10.1038/onc.2008.64

2. Murray-Zmijewski F, Lane DP, Bourdon J-C. 2006. P53/p63/p73 isoforms: an orchestra of isoforms to harmonise cell differentiation and response to stress. Cell Death Differ 13:962-972. https://doi.org/10.1038/sj.cdd.4401914
3. Di C, Yang L, Zhang H, Ma X, Zhang X, Sun C, Li H, Xu S, An L, Li X, Bai Z. 2013. Mechanisms, function and clinical applications of DNp73. Cell Cycle 12:1861-1867. https://doi.org/10.4161/cc.24967

4. Lee CW, La Thangue NB. 1999. Promoter specificity and stability control of the p53-related protein p73. Oncogene 18:4171-4181. https://doi.org/10.1038/sj.onc.1202793

5. Fontemaggi G, Kela I, Amariglio N, Rechavi G, Krishnamurthy J, Strano S, Sacchi A, Givol D, Blandino G. 2002. Identification of direct p73 target genes combining DNA microarray and chromatin immunoprecipitation analyses. J Biol Chem 277:43359-43368. https://doi.org/10.1074/jbc.M205573200

6. Accardi R, Fathallah I, Gruffat H, Mariggiò G, Le Calvez-Kelm F, Voegele C, Bartosch B, Hernandez-Vargas H, McKay J, Sylla BS, Manet E, Tommasino M. 2013. Epstein - Barr virus transforming protein LMP-1 alters B cells gene expression by promoting accumulation of the oncoprotein ΔNp73α. PLoS Pathog 9:e1003186. https://doi.org/10.1371/journal.ppat.1003186

7. Allart S, Martin H, Detraves C, Terrasson J, Caput D, Davrinche C. 2002. Human cytomegalovirus induces drug resistance and alteration of programmed cell death by accumulation of deltaN-p73alpha. J Biol Chem 277:29063-29068. https://doi.org/10.1074/jbc.M201974200

8. Accardi R, Dong W, Smet A, Cui R, Hautefeuille A, Gabet A-S, Sylla BS, Gissmann L, Hainaut P, Tommasino M. 2006. Skin human papillomavirus type 38 alters p53 functions by accumulation of deltaNp73. EMBO Rep 7:334-340. https://doi.org/10.1038/sj.embor.7400615

9. Cornet I, Bouvard V, Campo MS, Thomas M, Banks L, Gissmann L, Lamartine J, Sylla BS, Accardi R, Tommasino M. 2012. Comparative

analysis of transforming properties of E6 and E7 from different beta human papillomavirus types. J Virol 86:2366-2370. https://doi.org/10.1128/JVI.06579-11

10. Accardi R, Scalise M, Gheit T, Hussain I, Yue J, Carreira C, Collino A, Indiveri C, Gissmann L, Sylla BS, Tommasino M. 2011. IkappaB kinase beta promotes cell survival by antagonizing p53 functions through DeltaNp73alpha phosphorylation and stabilization. Mol Cell Biol 31:2210-2226. https://doi.org/10.1128/MCB.00964-10

11. Rollison DE, Viarisio D, Amorrtu RP, Gheit T, Tommasino M. 2019. An emerging issue in oncogenic virology: the role of beta human papillomavirus types in the development of cutaneous squamous cell carcinoma. J Virol 93:e01003-18. https://doi.org/10.1128/JVI.01003-18

12. Taverniti V, Krynska H, Venuti A, Straub M-L, Sirand C, Lohmann E, Romero-Medina MC, Moro S, Robitaille A, Negroni L, Martinez-Zapien D, Masson M, Tommasino M, Zanier K. 2023. The E2F4/p130 repressor complex cooperates with oncogenic ΔNp73α to inhibit gene expression in human papillomavirus 38 E6/E7-transformed keratinocytes and in cancer cells. mSphere 8:e0005623. https://doi.org/10.1128/msphere.00056-23

13. Rigaut G, Shevchenko A, Rutz B, Wilm M, Mann M, Séraphin B. 1999. A generic protein purification method for protein complex characterization and proteome exploration. Nat Biotechnol 17:1030-1032. https://doi.org/10.1038/13732

14. Tyanova S, Temu T, Sinitcyn P, Carlson A, Hein MY, Geiger T, Mann M, Cox J. 2016. The Perseus computational platform for comprehensive analysis of (prote)omics data. Nat Methods 13:731-740. https://doi.org/10.1038/nmeth.3901