Download MendeleyBECN2 interacts with ATG14 through a metastable coiled-coil to mediate autophagy.
Su, M., Li, Y., Wyborny, S., Neau, D., Chakravarthy, S., Levine, B., Colbert, C.L., Sinha, S.C.(2017) Protein Sci 26: 972-984
- PubMed: 28218432
- DOI: https://doi.org/10.1002/pro.3140
- Primary Citation of Related Structures:
5K7B, 5K9L - PubMed Abstract:
ATG14 binding to BECN/Beclin homologs is essential for autophagy, a critical catabolic homeostasis pathway. Here, we show that the α-helical, coiled-coil domain (CCD) of BECN2, a recently identified mammalian BECN1 paralog, forms an antiparallel, curved homodimer with seven pairs of nonideal packing interactions, while the BECN2 CCD and ATG14 CCD form a parallel, curved heterodimer stabilized by multiple, conserved polar interactions. Compared to BECN1, the BECN2 CCD forms a weaker homodimer, but binds more tightly to the ATG14 CCD. Mutation of nonideal BECN2 interface residues to more ideal pairs improves homodimer self-association and thermal stability. Unlike BECN1, all BECN2 CCD mutants bind ATG14, although more weakly than wild type. Thus, polar BECN2 CCD interface residues result in a metastable homodimer, facilitating dissociation, but enable better interactions with polar ATG14 residues stabilizing the BECN2:ATG14 heterodimer. These structure-based mechanistic differences in BECN1 and BECN2 homodimerization and heterodimerization likely dictate competitive ATG14 recruitment.
Organizational Affiliation:
Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota, 58108-6050.
