Despite the NPMmut decrease in Determine 11B was not statistically significant (= 3), we have previously shown that NPM mutation enhances the NPM monomer/oligomer ratio [28]. with p53 has not been investigated yet, although consequences of NPMmut-induced p53 export to the cytoplasm are important for understanding the oncogenic potential of these mutations. We investigated p53-NPM conversation in live HEK-293T cells by FLIM-FRET and in cell lysates by immunoprecipitation. eGFP lifetime-photoconversion was used to follow redistribution dynamics of NPMmut and p53 in Selinexor-treated cells. We confirmed the p53-NPMwt conversation in intact cells and newly documented that this conversation is not compromised by the NPM mutation causing displacement of p53 to the cytoplasm. Moreover, the conversation was not abolished for non-oligomerizing NPM variants with truncated oligomerization domain name, suggesting that oligomerization is not essential for conversation of WHI-P180 NPM forms with p53. Inhibition of the nuclear exporter XPO1 by Selinexor caused expected nuclear relocalization of both NPMmut and p53. However, significantly different return rates of these proteins indicate nontrivial mechanism of p53 and NPMmut cellular trafficking. The altered p53 regulation in cells expressing NPMmut offers improved understanding to help investigational strategies targeting these mutations. gene resulting in the altered C-terminus of NPM and aberrant localization WHI-P180 of mutated NPM to the cytoplasm appears in approximately 50% AML with normal CEACAM8 karyotype [10,29,30]. Leukemogenic potential of the mutation has not been elucidated yet. When it occurs as an isolated mutation without concurrent genetic aberrations, it stratifies the patient to the low-risk category [31]. Moreover, as refractory mutation, it is suitable for assessment of minimal residual disease (MRD) [32,33]. The original NoLS of wild-type NPM (NPMwt) is usually highly compromised in the mutated protein and strong nuclear export signal (NES) for the XPO1 exporter appears at the WHI-P180 WHI-P180 altered C-terminus [34,35] in addition to the two NESes already present in its N-terminal domain name [12]. The most frequent AML-related mutation type A gives rise to mutated protein lacking tryptophans W288 and W290 (NPMmutA, further abbreviated NPMmut) [36]. An alternative mutation of type E retains W288, which partially preserves nucleolar localization of the mutated protein (NPMmutE) [37]. The conversation of NPM monomers within the oligomer and its conversation with p14Arf were shown to persist in presence of the NPMmut [34]. Interacting proteins NPMwt and p14Arf become partially dislocated to the cytoplasm due to their binding to NPMmut [38]. In analogy, other NPM-interacting proteins, e.g., p53, are also candidates for such dislocation. The dislocation should interfere with their proapoptotic activity, which could lead to uncontrolled cell division [11]. On the WHI-P180 other hand, the conversation of NPM with NCL, taking place through AA187-241 region of the NPM molecule [21], is usually inhibited by the NPM mutation and NCL is usually therefore not translocated to the cytoplasm together with NPMmut [28]. Since p53 was found to interact with a domain near the C-terminus of NPM (AA186-259 or AA242-269, respectively) [3,4], one could expect that this p53-NPM conversation was affected by this mutation as well. The detailed mechanism and role of the p53-NPMmut conversation in the leukemogenesis is usually unknown so far. The main part of this article therefore investigates impact of the NPM mutation around the p53-NPM conversation. This conversation is usually confirmed in cell lysates, and we also newly document it in live cells. Importantly, we bring evidence that this mutation has no impact on this conversation. Cytoplasmic localization of p53 plays an adverse role in the cell cycle regulation [39] and it was reported to launch apoptosis via conversation with mitochondrial proapoptotic factors [40]. On the other hand,.