Small glutamine-rich tetratricopeptide repeat-containing protein alpha (Alpha-SGT) (Vpu-binding protein) (UBP)
1_MDNKK 6_ RLAYA 11_ IIQFL 16_ HDQLR 21_ HGGLS 26_ SDAQE 31_ SLEVA 36_ IQCLE 41_ TAFGV 46_ TVEDS 51_ DLALP 56_ QTLPE 61_ IFEAA 66_ ATGKE 71_ MPQDL 76_ RSPAR 81_ TPPSE 86_ EDSAE 91_ AERLK 96_ TEGNE 101_ QMKVE 106_ NFEAA 111_ VHFYG 116_ KAIEL 121_ NPANA 126_ VYFCN 131_ RAAAY 136_ SKLGN 141_ YAGAV 146_ QDCER 151_ AICID 156_ PAYSK 161_ AYGRM 166_ GLALS 171_ SLNKH 176_ VEAVA 181_ YYKKA 186_ LELDP 191_ DNETY 196_ KSNLK 201_ IAELK 206_ LREAP 211_ SPTGG 216_ VGSFD 221_ IAGLL 226_ NNPGF 231_ MSMAS 236_ NLMNN 241_ PQIQQ 246_ LMSGM 251_ ISGGN 256_ NPLGT 261_ PGTSP 266_ SQNDL 271_ ASLIQ 276_ AGQQF 281_ AQQMQ 286_ QQNPE 291_ LIEQL 296_ RSQIR 301_ SRTPS 306_ASNDD
1: Co-chaperone that binds misfolded and hydrophobic patches-containing client proteins in the cytosol. Mediates their targeting to the endoplasmic reticulum but also regulates their sorting to the proteasome when targeting fails (PubMed:28104892). Functions in tail-anchored/type II transmembrane proteins membrane insertion constituting with ASNA1 and the BAG6 complex a targeting module (PubMed:28104892). Functions upstream of the BAG6 complex and ASNA1, binding more rapidly the transmembrane domain of newly synthesized proteins (PubMed:25535373, PubMed:28104892). It is also involved in the regulation of the endoplasmic reticulum-associated misfolded protein catabolic process via its interaction with BAG6: collaborates with the BAG6 complex to maintain hydrophobic substrates in non-ubiquitinated states (PubMed:23129660, PubMed:25179605). Competes with RNF126 for interaction with BAG6, preventing the ubiquitination of client proteins associated with the BAG6 complex (PubMed:27193484). Binds directly to HSC70 and HSP70 and regulates their ATPase activity (PubMed:18759457)
2: (Microbial infection) In case of infection by polyomavirus, involved in the virus endoplasmic reticulum membrane penetration and infection via interaction with DNAJB12, DNAJB14 and HSPA8/Hsc70 (PubMed:24675744)