The simian immunodeficiency virus (SIV) Nef protein contains a consensus Src-homology 3 (SH3) binding motif. However, no SH3-domain proteins showing strong binding to SIV Nef have yet been found, and its potential capacity for high-affinity SH3 binding has therefore remained unproven. Here we have used phage-display-assisted protein engineering to develop artificial SH3 domains that bind tightly to SIV strain mac (SIVmac) Nef. Substitution of six amino acids in the RT loop region of Hck-SH3 with the sequence E/DGWWG resulted in SH3 domains that bound in vitro to SIVmac Nef much better than the natural Hck- or Fyn-SH3 domains. These novel SH3 domains also efficiently associated with SIVmac Nef when co-expressed in 293T cells and displayed a strikingly differential specificity when compared with SH3 domains similarly targeted for binding to human immunodeficiency virus type 1 (HIV-1) Nef. Thus, SIVmac Nef is competent for high-affinity SH3 binding, but its natural SH3 protein partners are likely to be different from those of HIV-1 Nef.
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http://dx.doi.org/10.1099/0022-1317-83-12-3147 | DOI Listing |
Mol Divers
January 2025
Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education (MAHE), Manipal, 576104, India.
SH2 (Src Homology 2) domains play a crucial role in phosphotyrosine-mediated signaling and have emerged as promising drug targets, particularly in cancer therapy. STAT3 (Signal Transducer and Activator of Transcription 3), which contains an SH2 domain, plays a pivotal role in cancer progression and immune evasion because it facilitates the dimerization of STAT3, which is essential for their activation and subsequent nuclear translocation. SH2 domain-mediated STAT3 inhibition disrupts this binding, reduces phosphorylation of STAT3, and impairs dimerization.
View Article and Find Full Text PDFCell Death Dis
January 2025
Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, 60438, Frankfurt, Germany.
The transcription factor p63 is expressed in many different isoforms as a result of differential promoter use and splicing. Some of these isoforms have very specific physiological functions in the development and maintenance of epithelial tissues and surveillance of genetic integrity in oocytes. The ASPP family of proteins is involved in modulating the transcriptional activity of the p53 protein family members, including p63.
View Article and Find Full Text PDFArch Biochem Biophys
February 2025
Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China; The Second Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China. Electronic address:
Protein Sci
January 2025
Department of Physics, University of Toronto, Toronto, Ontario, Canada.
The point mutation N642H of the signal transducer and activator of transcription 5B (STAT5B) protein is associated with aggressive and drug-resistant forms of leukemia. This mutation is thought to promote cancer due to hyperactivation of STAT5B caused by increased stability of the active, parallel dimer state. However, the molecular mechanism leading to this stabilization is not well understood as there is currently no structure of the parallel dimer.
View Article and Find Full Text PDFNat Commun
December 2024
Institute of Physiological Chemistry, Faculty of Medicine, Philipps University of Marburg, Marburg, Germany.
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