Journal: bioRxiv
Article Title: Spinal cord phosphoproteome of a SCA2/ALS13 mouse model reveals alteration of ATXN2-N-term SH3-actin interactome and of autophagy via WNK1-MYO6-OPTN-SQSTM1
doi: 10.1101/2024.11.06.622233
Figure Lengend Snippet: (A) Schematic summary of phospho-regulation events of proteolysis and aggrephagy in the terminal-stage spinal cord of the Atxn2 -CAG100-KIN mouse model of SCA2/ALS13. The potential co-aggregation of ATXN2 (black clusters) with SH3-containing interactors and competing PRM-containing proteins that show differential phosphorylation is highlighted in a field with a gray background. Proteins potentially undergoing LLPS are highlighted in red letters, ALS disease proteins in bold letters. (B) Schematic protein structures and Q100-ATXN2-triggered differential phosphorylation events for ATXN2 as aggregating disease protein and for SQSTM1 as the main selective aggrephagy receptor, illustrating that massive hyperphosphorylations are flanking the Q100-KIN mutation replacing murine residue Q156 (purple line) and the three PRMs (deep blue square, with mouse residue numbers) in the N-terminus of ATXN2, and are targeting the ZZ (light gray square) and LIR (deep green column) domains of SQSTM1. Hypophosphorylations across remaining ATXN2 likely reflect its reduced abundance upon polyQ expansion . The numbering of residues adheres to UniProt reference sequences, ignoring the unstable polyQ repeat KIN in ATXN2. Proteins are represented by their gene symbols, phosphorylated residue numbers are shown for serine (S), threonine (T) or tyrosine (Y). IDR = intrinsically disordered region, prone to phase separation; LIR = LC3-interacting region; KIR = Keap1-interacting region; PB1 = Phox and Bem1p; PtdIns3P = phosphatidylinositol 3-phosphate; RTK = receptor tyrosine kinase; TBS = TRAF6-binding sequence; UBA = ubiquitin-associated; ZZ = Zinc finger domain.
Article Snippet: The following primary antibodies were used: ATXN2 (Proteintech 21776–1-AP, 1:1000), BNIP3 (Proteintech 68091-1-Ig, 1:1000), CTSB (Abcam ab214428, 1:1000), LC3 A/B (Cell Sig-naling 4108, 1:1000), NBR1 (Cell Signaling 9891, 1:500), OPTN (Proteintech 10837-1-AP, 1:1000), PPIA (Proteintech 10720-1-AP, 1:1000), SQSTM1/p62 (Cell Signaling 39749, 1:1000), TAX1BP1 (Proteintech 14424-1-AP, 1:1000), UBQLN2 (Novus Biologicals NBP2-25164, 1:1000), WDFY3 (Proteintech 55009-1-AP, 1:1000), WNK1 (Invitrogen PA5-28382, 1:1000).
Techniques: Phospho-proteomics, Mutagenesis, Residue, Binding Assay, Sequencing, Ubiquitin Proteomics