A highly conserved glutamic acid in ALFY inhibits membrane binding to aid in aggregate clearance. (1st December 2020)

• Record Type: Journal Article
• Authors: Reinhart, Erin F.; Litt, Nicole A.; Katzenell, Sarah; Pellegrini, Maria; Yamamoto, Ai; Ragusa, Michael J.
• Is Part Of: Traffic. Volume 22:Number 1/2(2021)
• Page Start: 23
• Page End: 37
• Publication Date: 2020-12-01
• Subjects: ALFY -- autophagy -- FYVE domain -- nuclear magnetic resonance spectroscopy -- phosphatidylinositol 3‐phosphate -- protein structure; Biological transport -- Periodicals; 571.6
• DOI: 10.1111/tra.12771
• Languages: English
• ISSNs: 1398-9219

Abstract

Abstract: 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. Abstract : ALFY is a FYVE domain containing protein involved in the clearance of misfolded aggregates, including huntingtin, by autophagy. We have demonstrated that the FYVE domain of ALFY contains a highly conserved glutamic acid within its membrane insertion loop that is not present in any other human FYVE domain. This glutamic acid dramatically reduces the ability of ALFY to bind membranes in vitro and in vivo and is required for efficient aggregate clearance.