title: Sprouty 2 binds ESCRT-II factor Eap20 and facilitates HIV-1 gag release.
abstract: The four ESCRT (endocytic sorting complexes required for transport) complexes (ESCRT-0, -I, -II, and -III) normally operate sequentially in the trafficking of cellular cargo. HIV-1 Gag trafficking and release as virus-like particles (VLPs) require the participation of ESCRTs; however, its use of ESCRTs is selective and nonsequential. Specifically, Gag trafficking to release sites on the plasma membrane does not require ESCRT-0 or -II. It is known that a bypass of ESCRT-0 is achieved by the direct linkage of the ESCRT-I component, Tsg101, to the primary L domain motif (PTAP) in Gag and that bypass of ESCRT-II is achieved by the linkage of Gag to ESCRT-III through the adaptor protein Alix. However, the mechanism by which Gag suppresses the interaction of bound ESCRT-I with ESCRT-II is unknown. Here we show (i) that VLP release requires the steady-state level of Sprouty 2 (Spry2) in COS-1 cells, (ii) that Spry2 binds the ESCRT-II component Eap20, (iii) that binding Eap20 permits Spry2 to disrupt ESCRT-I interaction with ESCRT-II, and (iv) that coexpression of Gag with a Spry2 fragment that binds Eap20 increases VLP release. Spry2 also facilitated release of P7L-Gag (i.e., release in the absence of Tsg101 binding). In this case, rescue required the secondary L domain (YPX(n)L) in HIV-1 Gag that binds Alix and the region in Spry2 that binds Eap20. The results identify Spry2 as a novel cellular factor that facilitates release driven by the primary and secondary HIV-1 Gag L domains.
authors.affiliation: Life Sciences Bldg., Rm. 248, Department of Molecular Genetics & Microbiology, Stony Brook University, Stony Brook, NY 11794-5222, USA.
authors.forename: G N
authors.initials: GN
authors.lastname: Medina
authors.forename: L S
authors.initials: LS
authors.lastname: Ehrlich
authors.forename: M H
authors.initials: MH
authors.lastname: Chen
authors.forename: M B
authors.initials: MB
authors.lastname: Khan
authors.forename: M D
authors.initials: MD
authors.lastname: Powell
authors.forename: C A
authors.initials: CA
authors.lastname: Carter
mesh_terms: D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism*; D015683:Gene Products, gag / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011485:Protein Binding; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D004268:DNA-Binding Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D015683:Gene Products, gag; D009419:Nerve Tissue Proteins