The Mechanism of p53 Rescue by SUSP4.

p53 is an important tumor-suppressor protein deactivation of which by mdm2 results in cancers. A SUMO-specific protease 4 (SUSP4) was shown to rescue p53 from mdm2-mediated deactivation, but the mechanism is unknown. The discovery by NMR spectroscopy of a "p53 rescue motif" in SUSP4 that disrupts p53-mdm2 binding is presented. This 29-residue motif is pre-populated with two transient helices connected by a hydrophobic linker. The helix at the C-terminus binds to the well-known p53-binding pocket in mdm2 whereas the N-terminal helix serves as an affinity enhancer. The hydrophobic linker binds to a previously unidentified hydrophobic crevice in mdm2. Overall, SUSP4 appears to use two synergizing modules, the p53 rescue motif described here and a globular-structured SUMO-binding catalytic domain, to stabilize p53. A p53 rescue motif peptide exhibits an anti-tumor activity in cancer cell lines expressing wild-type p53. A pre-structures motif in the intrinsically disordered proteins is thus important for target recognition.

Beyond burnout: a four-year survey of osteopathic medical student mental health and the implications for the development of wellness and mental health programs.

CONTEXT: The mental health crisis in medicine cannot be explained by burnout alone. Physicians are not immune to this crisis and are known to have higher rates of suicide and depression than the general population. A high prevalence of mental health symptoms has been observed in early medical training. OBJECTIVES: This study was completed to characterize medical students' mental well-being and provide guidance for timely intervention. METHODS: An annual prospective, voluntary, anonymous, cross-sectional survey of medical students was completed over a 4-year period in medical school from 2016 to 2019. The survey was created based on standardized psychiatric screening tools assessing symptoms of depression, anxiety, burnout, and sleep problems. In each of those years, 1,257 (2016), 1,254 (2017), 1,221 (2018), and 1,220 (2019) enrolled students, respectively, were invited to participate. Data on students' mental health were analyzed in relation to their year of school separately for each survey year utilizing SAS 9.4. RESULTS: A total of 973 students in 2016, 889 students in 2017, 547 students in 2018, and 606 students in 2019 participated in the study. For depression and burnout subscales, an increase in symptom scores were observed every survey year (2016, 2017, 2018, and 2019) by the second or third year of medical school with a clinically significant effect size. Persistently high levels of anxiety were observed throughout medical school, with significant increases after the first year noted in the 2016 and 2017 surveys, but not in the 2018 or 2019 surveys. Similarly, significant changes in sleep disturbance were found in the 2016 and 2017 surveys, but not in 2018 or 2019. CONCLUSIONS: Symptoms of burnout, depression, and anxiety were observed throughout all four years of medical school, with increases starting after the first year. Early intervention is needed to support students' mental health and increase access to care and resources.

Understanding pre-structured motifs (PreSMos) in intrinsically unfolded proteins.

Intrinsically unfolded proteins (IUPs) do not obey the golden rule of structural biology, 3D structure = function, as they manifest their inherent functions without resorting to three-dimensional structures. Absence of a compact globular topology in these proteins strongly implies that their ligand recognition processes should involve factors other than spatially well-defined binding pockets. Heteronuclear multidimensional (HetMulD) NMR spectroscopy assisted with a stable isotope labeling technology is a powerful tool for quantitatively investigating detailed structural features in IUPs. In particular, it allows us to delineate the presence and locations of pre-structured motifs (PreSMos) on a per-residue basis. PreSMos are the transient local structural elements that presage target-bound conformations and act as specificity determinants for IUP recognition by target proteins. Here, we present a brief chronicle of HetMulD NMR studies on IUPs carried out over the past two decades along with a discussion on the functional significance of PreSMos in IUPs.