TY - JOUR
T1 - BECN2 interacts with ATG14 through a metastable coiled-coil to mediate autophagy
AU - Su, Minfei
AU - Li, Yue
AU - Wyborny, Shane
AU - Neau, David
AU - Chakravarthy, Srinivas
AU - Levine, Beth
AU - Colbert, Christopher L.
AU - Sinha, Sangita C.
N1 - Publisher Copyright:
© 2017 The Protein Society
PY - 2017/5/1
Y1 - 2017/5/1
N2 - 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.
AB - 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.
KW - ATG14
KW - BECN2
KW - BECN2:ATG14 heterodimer
KW - autophagy
KW - coiled-coil domain
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U2 - 10.1002/pro.3140
DO - 10.1002/pro.3140
M3 - Article
C2 - 28218432
AN - SCOPUS:85014931958
SN - 0961-8368
VL - 26
SP - 972
EP - 984
JO - Protein Science
JF - Protein Science
IS - 5
ER -