2MVL: Solution structure of cytosolic part of Trop2

Trop2 is a transmembrane signaling glycoprotein upregulated in stem and carcinoma cells. Proliferation-enhancing signaling involves regulated intramembrane proteolytic release of a short cytoplasmic fragment, which is later engaged in a cytosolic signaling complex. We propose that Trop2 function is modulated by phosphorylation of a specific serine residue within this cytosolic region (Ser303), and by proximity effects exerted on the cytosolic tail by Trop2 dimerization. Structural characterization of both the transmembrane (Trop2TM) and cytosolic regions (Trop2IC) support this hypothesis, and shows that the central region of Trop2IC forms an alpha-helix. Comparison of NMR structures of non-phosphorylated and phosphorylated forms suggest that phosphorylation of Trop2IC triggers salt bridge reshuffling, resulting in significant conformational changes including ordering of the C-terminal tail. In addition, we demonstrate that the cytosolic regions of two Trop2 subunits can be brought into close proximity via transmembrane part dimerization. Finally, we show that Ser303-phosphorylation significantly affects the structure and accessibility of functionally important regions of the cytosolic tail. These observed structural features of Trop2 at the membrane-cytosol interface could be important for regulation of Trop2 signaling activity.
PDB ID: 2MVLDownload
MMDB ID: 128971
PDB Deposition Date: 2014/10/8
Updated in MMDB: 2018/05
Experimental Method:
solution nmr
Similar Structures:
Biological Unit for 2MVL: monomeric; determined by author
Molecular Components in 2MVL
Label Count Molecule
Protein (1 molecule)
Tumor-associated Calcium Signal Transducer 2(Gene symbol: TACSTD2)
Molecule annotation
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