ARG82 (YDR173C, P07250) notes

• Inositol polyphosphate multikinase (IPMK; ArgRIII/Ipk2/Gsl3). Predominant in vivo route Ins(1,4,5)P3 -> Ins(1,4,5,6)P4 -> Ins(1,3,4,5,6)P5 [UniProt:P07250 "Its predominant in vivo catalytic function is to convert Ins(1,4,5)P3 to Ins(1,4,5,6)P4 to Ins(1,3,4,5,6)P5 via 6- and 3-kinase activities"].
• Purified yeast IP3 kinase is a 6-kinase PMID:7945194; identified as Arg82 PMID:10720331.
• Converts IP3 to higher IPs PMID:10574768; IP6 step is actually Ipk1.
• Also IP4(1,3,4,5) 6-kinase and IP5 pyrophosphorylation to PP-IP4 PMID:11311242.
• arg82 null: IP3 up 170-fold, IP6 down 100-fold, mRNA export defect PMID:10683435; sole IP3 kinase PMID:22992733.
• Nuclear PMID:3311884; nuclear PI3K activity reported PMID:16123124 - kept non-core.
• Kinase-independent role: stabilizes Mcm1/Arg80 via polyaspartate domain PMID:10632874; PMID:12828642; PMID:22992733.
• Not a stable component of the DNA-bound complex PMID:10632874 -> RNAPII TF complex NAS marked over-annotated.
• PHO/NCR effects need kinase activity (indirect via PP-InsPs) PMID:12828642.

Curation decisions

• GO:0120517 (IP5 -> IP6) from YeastPathways RCA is a mis-mapping of the IP5 -> PP-IP4 reaction: MODIFY to GO:0000827. The same mis-mapping affects KCS1.
• Cytoplasm IBA (IP6K/ITPK donors) and cytosol RCA (pathway default) marked over-annotated; all yeast data say nuclear.
• Macroautophagy IMP from a genome-wide mitophagy screen (PMID:19793921) marked over-annotated (pleiotropic deletion).