A highly conserved glutamic acid in ALFY inhibits membrane binding to aid in aggregate clearance

Traffic. 2021 Jan;22(1-2):23-37. doi: 10.1111/tra.12771. Epub 2020 Dec 1.


Autophagy-linked FYVE protein (ALFY) is a large, multidomain protein involved in the degradation of protein aggregates by selective autophagy. The C-terminal FYVE domain of ALFY has been shown to bind phosphatidylinositol 3-phosphate (PI(3)P); however, ALFY only partially colocalizes with other FYVE domains in cells. Thus, we asked if the FYVE domain of ALFY has distinct membrane binding properties compared to other FYVE domains and whether these properties might affect its function in vivo. We found that the FYVE domain of ALFY binds weakly to PI(3)P containing membranes in vitro. This weak binding is the result of a highly conserved glutamic acid within the membrane insertion loop in the FYVE domain of ALFY that is not present in any other human FYVE domain. In addition, not only does this glutamic acid reduce binding to membranes in vitro and inhibits its targeting to membranes in vivo, but it is also important for the ability of ALFY to clear protein aggregates.

Keywords: ALFY; FYVE domain; autophagy; nuclear magnetic resonance spectroscopy; phosphatidylinositol 3-phosphate; protein structure.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Signal Transducing*
  • Autophagy-Related Proteins
  • Glutamic Acid*
  • Humans
  • Phosphatidylinositol Phosphates


  • Adaptor Proteins, Signal Transducing
  • Autophagy-Related Proteins
  • Phosphatidylinositol Phosphates
  • WDFY3 protein, human
  • phosphatidylinositol 3-phosphate
  • Glutamic Acid