Structural insights into the tumor-promoting function of the MTDH-SND1 complex

Area of Science:

• Molecular Biology
• Structural Biology
• Cancer Research

Background:

• Metadherin (MTDH) and Staphylococcal nuclease domain containing 1 (SND1) are frequently overexpressed in various cancers.
• The specific structural mechanisms underlying the MTDH-SND1 interaction and its functional consequences are not well understood.

Purpose of the Study:

• To elucidate the high-resolution crystal structure of the MTDH-SND1 complex.
• To understand the structural basis of MTDH-SND1 interaction and its role in cancer progression.

Main Methods:

• High-resolution crystal structure determination of the MTDH-SND1 complex.
• Analysis of protein-protein interaction interfaces and binding pockets.

Main Results:

• The crystal structure revealed an 11-residue MTDH peptide motif binding within an extended groove of SND1, involving two tryptophan residues of MTDH fitting into specific pockets on SND1.
• SND1 exhibits protruding arms and valleys at the interface, suggesting potential for additional interactions.
• Interactions within the tryptophan-binding pockets are critical for MTDH and SND1 functions in breast cancer and for SND1 stability under stress conditions.

Conclusions:

• The study reveals a unique binding mode between MTDH and SND1, mediated by MTDH tryptophan residues engaging with SND1 pockets.
• This interaction mode is essential for the cancer-promoting activities of MTDH and SND1.
• The findings provide a structural foundation for understanding MTDH-SND1 signaling pathways and offer potential therapeutic targets for cancer treatment.