Figure 1.

Crystallographic Structure of HD-PTP_CC

(A) Diagram of HD-PTP domain structure indicating domain boundaries and sites of interaction for ESCRT partners. The position of the conserved FYX₂L motif in the CC domain is shown, as well as the FPXL motif in UBAP1.

(B) Cartoon diagram of the HD-PTP_CC crystal structure. HD-PTP_CC resembles an ice hockey stick, where the N-terminal region represents the blade and the C-terminal region is the shaft. The seven α helices are labeled H1 to H7, with H7 being the central and longest helix extending the whole length of the structure.

(C) Coiled-coil motifs in the HD-PTP_CC structure after analysis with SOCKET (Walshaw and Woolfson, 2001). HD-PTP_CC contains two canonical coiled coils: one two-stranded coiled coil (2st-cc) in the blade and one three-stranded coiled coil (3st-cc) in the shaft.

(D) Topology diagram of the structure of HD-PTP_CC showing the arrangement of the seven α helices.

(E) Superimposition of the HD-PTP_CC (red) and Alix_V (blue) structures. The Alix_V crystal structure (PDB: 2OJQ) shows a V-shaped helical protein in a closed conformation, in contrast to the open and extended conformation of HD-PTP_CC. The two arms in Alix_V are labeled.

(F) Superposition of the structures of Alix_V (blue) and yeast Bro1_V (orange, PDB: 4JIO). Both structures contain two arms joined by flexible loops.