| Structural highlights
Function
FBXW7_HUMAN Substrate recognition component of a SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Probably recognizes and binds to phosphorylated target proteins. Involved in the degradation of cyclin-E, MYC, NOTCH1 released notch intracellular domain (NICD), and probably PSEN1.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
c-Myc (hereafter, Myc) is a cancer driver whose abundance is regulated by the SCF(Fbw7) ubiquitin ligase and proteasomal degradation. Fbw7 binds to a phosphorylated Myc degron centered at threonine 58 (T58), and mutations of Fbw7 or T58 impair Myc degradation in cancers. Here, we identify a second Fbw7 phosphodegron at Myc T244 that is required for Myc ubiquitylation and acts in concert with T58 to engage Fbw7. While Ras-dependent Myc serine 62 phosphorylation (pS62) is thought to stabilize Myc by preventing Fbw7 binding, we find instead that pS62 greatly enhances Fbw7 binding and is an integral part of a high-affinity degron. Crystallographic studies revealed that both degrons bind Fbw7 in their diphosphorylated forms and that the T244 degron is recognized via a unique mode involving Fbw7 arginine 689 (R689), a mutational hotspot in cancers. These insights have important implications for Myc-associated tumorigenesis and therapeutic strategies targeting Myc stability.
Two diphosphorylated degrons control c-Myc degradation by the Fbw7 tumor suppressor.,Welcker M, Wang B, Rusnac DV, Hussaini Y, Swanger J, Zheng N, Clurman BE Sci Adv. 2022 Jan 28;8(4):eabl7872. doi: 10.1126/sciadv.abl7872. Epub 2022 Jan , 28. PMID:35089787[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Strohmaier H, Spruck CH, Kaiser P, Won KA, Sangfelt O, Reed SI. Human F-box protein hCdc4 targets cyclin E for proteolysis and is mutated in a breast cancer cell line. Nature. 2001 Sep 20;413(6853):316-22. PMID:11565034 doi:http://dx.doi.org/10.1038/35095076
- ↑ Wu G, Lyapina S, Das I, Li J, Gurney M, Pauley A, Chui I, Deshaies RJ, Kitajewski J. SEL-10 is an inhibitor of notch signaling that targets notch for ubiquitin-mediated protein degradation. Mol Cell Biol. 2001 Nov;21(21):7403-15. PMID:11585921 doi:http://dx.doi.org/10.1128/MCB.21.21.7403-7415.2001
- ↑ Yada M, Hatakeyama S, Kamura T, Nishiyama M, Tsunematsu R, Imaki H, Ishida N, Okumura F, Nakayama K, Nakayama KI. Phosphorylation-dependent degradation of c-Myc is mediated by the F-box protein Fbw7. EMBO J. 2004 May 19;23(10):2116-25. Epub 2004 Apr 22. PMID:15103331 doi:http://dx.doi.org/10.1038/sj.emboj.7600217
- ↑ Popov N, Herold S, Llamazares M, Schulein C, Eilers M. Fbw7 and Usp28 regulate myc protein stability in response to DNA damage. Cell Cycle. 2007 Oct 1;6(19):2327-31. Epub 2007 Jul 26. PMID:17873522
- ↑ Popov N, Wanzel M, Madiredjo M, Zhang D, Beijersbergen R, Bernards R, Moll R, Elledge SJ, Eilers M. The ubiquitin-specific protease USP28 is required for MYC stability. Nat Cell Biol. 2007 Jul;9(7):765-74. Epub 2007 Jun 10. PMID:17558397 doi:http://dx.doi.org/10.1038/ncb1601
- ↑ Welcker M, Wang B, Rusnac DV, Hussaini Y, Swanger J, Zheng N, Clurman BE. Two diphosphorylated degrons control c-Myc degradation by the Fbw7 tumor suppressor. Sci Adv. 2022 Jan 28;8(4):eabl7872. PMID:35089787 doi:10.1126/sciadv.abl7872
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