Table 1.

Summarized description of polyQ SCA-causative genes, protein molecular function and main interactors

Disease	SCA1	SCA2	MJD/SCA3	SCA6	SCA7	SCA17	DRPLA
Gene	ATXN1	ATXN2	ATXN3	CACNA1A	ATXN7	TBP	ATN1
Chromosome location	6p22.3	12q24.12	14q32.12	19p13.13	3p14.1	6q27	12p13.31
Repeat location	Exon 8	Exon 1	Exon 10	Exon 47	Exon 1	Exon 3	Exon 5
Protein molecular function	Transcription cofactor (regulates RNA transcription and processing)	RNA binding protein implicated in mRNA translation	Deubiquitinase involved in the ubiquitin–proteasome system and transcriptional regulation	Voltage-gated calcium channel subunit (Cav2.1)/transcription factor (ɑ1ACT)	Component of SAGA acetyltransferase complex (transcription coactivator)	General transcription factor from the TFIID complex	Transcription cofactor (recruits DNA-binding proteins to repress transcription)
Interactors (in vitro and/or in vivo)	ATXN1, ATXN1L (BOAT), CIC, HDAC3/4, MEF2, ANP32A (LANP), PQBP1, RBM17, RORA/KAT5 (TIP60), SMRT/NCoR2, RBPJ (CBF1), RFX1, ZBTB5, ZKSCAN1, USP7, UBQLN4 (A1U), COIL, GAPDH, YWHAE (14–3-3 protein)	ATXN2L, PABP, RBFOX1 (A2BP1), DDX6, TDP-43, STAU1, endophilins (SH3GL2/SH3GL3)/CBL/CIN85, RAD23A/B (HR23A/B), VCP, UBR2, α-tubulin, caspase-7, PARK2	CBP/PCAF/P300, HDAC3/SMRT, FOXO4, TBP, PML, beclin-1	CABP1 and SNARE proteins (STX1A and SNAP-25; for Cav2.1 channel), AT-rich and CA-rich DNA elements (for ɑ1ACT)	SAGA proteins (such as ATXN7L3, GCN5, TRRAP, TAF10), CRX, SIRT1, RORA, TBP, HDAC3, α-tubulin, SORBS1 (SH3P12), PSMC1 (S4)	DNA elements, TFIIB, TAFs (TAF1A, TAF1B, TAF1C), NCOA6 (ASC2), DRAP1 (NC2A), DR1 (NC2B), ELF3 (ESX), SPIB, SNAPC1, SNAPC2, SNAPC4, UTF1, BRF2 (BRFU), UBTF (UBF), HSF1, XBP1, MYOD, SP1, NF-γ, PAX5	RERE, HDAC1/2, CBP/TAF4, TBP, MTG8, BAIAP2 (IRSp53), WW domain containing proteins (WWP1, WWP2, WWP3), DVL1, NR2E1 (TLX), FAT1, ITCH, beclin-1
References	Koshy et al. (1996); Matilla et al. (1997); Davidson et al. (2000); Okazawa et al. (2002); Hong et al. (2002, 2003); Chen et al. (2003); Tsai et al. (2004); Mizutani et al. (2005); Serra et al. (2006); Lam et al. (2006); Bolger et al. (2007); Lim et al. (2008); Tong et al. (2011); Gehrking et al. (2011); Suter et al. (2013); Venkatraman et al. (2014); Kim et al. (2014); Coffin et al. (2023)	Shibata et al. (2000); Figueroa and Pulst (2003); Nicastro et al. (2005); Satterfield and Pallanck (2006); Nonhoff et al. (2007); Nonis et al. (2008); Elden et al. (2010); Kaehler et al. (2012); Paul et al. (2018; Weishäupl et al. (2019)	Chai et al. (2001); Li et al. (2002); Evert et al. (2006); Araujo et al. (2011); Ashkenazi et al. (2017); Feng et al. (2018)	Atlas et al. (2001); Lee et al. (2002); Cohen-Kutner et al. (2010); Du et al. (2013)	La Spada et al. (2001); Lebre et al. (2001); Matilla et al. (2001); Chen et al. (2004); Helmlinger et al. (2004); Ström et al. (2005); Zhao et al. (2008); Köhler et al. (2010; Nakamura et al. (2012); Duncan et al. (2013); Stoyas et al. (2017); Papai et al. 2020)	Ha et al. (1993); Kwon and Green (1994); Comai et al. (1994); Fukushima et al. (1998); Heller and Bengal (1998); Chang et al. (1999); Lee et al. (1999); Yuan and Gurley (2000); Čabart and Murphy (2001); Kamada et al. (2001); Hinkley et al. (2003); Friedman et al. (2007, 2008); Shah et al. (2009); Yang et al. (2014); Gouge et al. (2015)	Wood et al. (1998, 2000); Okamura-Oho et al. (1999); Shimohata et al. (2000); Yanagisawa et al. (2000); Nucifora et al. (2001); Feng et al. (2004); Zhang et al. (2006); Wang et al. (2008); Hou and Sibinga (2009); Ashkenazi et al. (2017)

SAGA, Spt-Ada-Gcn5- acetyltransferase. SNARE, soluble N-ethylmaleimide-sensitive factor activating protein receptor