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[Preprint]. 2024 Nov 1:2024.10.30.620932. [Version 1] doi: 10.1101/2024.10.30.620932

Figure 3. AAGAB psGD utilizes a unique interface to interact with sigma subunits.

Figure 3

(a) Cartoon and surface representation of AAGAB psGD:AP1σ3 complex structure with psGD in gold and AP1σ3 in violet. N- and C- termini of both proteins are labeled. Key interfacial residues on psGD are shown as sticks and labeled. In the right panel, the complex is rotated by 70 degrees and AP1σ3 is shown as electrostatic surface. Residues missing electron densities are represented by the dashed line. (b) Zoomed-in view of the psGD D151/F153/E155 interaction with AP1σ3. (c) Zoomed-in view of psGD A168 and K52/Y53 interactions with AP1σ3. (d) Superposition of the AAGAB psGD:AP1σ3 with the AP1σ:pSTING complex (PDB ID 7R4H). The AP1σ is colored gray and the pSTING peptide is shown as stick in pale yellow. F153 in AAGAB psGD and V98 in AP1σ3 are shown as sticks and colored orange and violet, respectively. (e) Superposition of the AAGAB psGD:AP1σ3 with the AP2core in complex with two cargo peptides (PDB ID 6QH6). The AP2σ is colored gray and the peptide is shown as stick in pale green. F153 in AAGAB psGD and V98 in AP1σ3 are shown as sticks and colored orange and violet, respectively. (f) Superposition of the AAGAB psGD:AP1σ3 with AP1 core in closed form (PDB ID 1W63). The AP1β and AP1μ subunits are shown as surface and colored in blue and yellow. (g) Superposition of psGD: AP1σ3 with HRas: RasGAP structure (PDB ID 1WQ1). AAGAB psGD and AP1σ3 are colored gold and violet as in (a). HRas and RasGAP are colored in gray and greencyan, respectively. The switch I and II regions of HRas are highlighted in red. (h) GST pull-down gel of GST-AP1σ3 co-expressed with His6-SUMO tagged WT or mutant AAGAB psGD. AR: A168R; 2YR: Y53R/Y54R; DEF3R: D151R/F153R/E155R. Ulp1 protease treatment is used to confirm the identity of His6-SUMO-AAGAB psGDWT. (i) GST pull-down gel of GST-AP2σ1 co-expressed with His6-SUMO tagged WT or mutant AAGAB psGD. AR: A168R; 2YR: Y53R/Y54R; DEF3R: D151R/F153R/E155R. Ulp1 protease treatment is used to confirm the identity of His6-SUMO-AAGAB psGDWT. Note that the molecular weights of GST-AP2σ1 and His6-SUMO-AAGAB psGD are too close for separation on SDS-PAGE.