ARR1 notes (Q940D0, At3g16857)

2026-10-05 review session (cytokinin two-component signaling module)

• Identity checked: UniProt Q940D0 ARR1_ARATH, At3g16857.
• Deep research tooling failed; review from cached publications.
• Nuclear transcriptional activator with sequence-specific DNA binding PMID:11135105.
• Directly activates ARR6 after cytokinin perception PMID:11691951.
• Redundancy with ARR10/ARR12 [PMID:16227453; PMID:18723577 "transcriptional regulation by ARR1, ARR10, and ARR12"].
• Root meristem size via SHY2 [PMID:19039136; PMID:17363254]; WUS activation in SAM/regeneration [PMID:28576846; PMID:28389585]; negative regulator of drought tolerance PMID:26884175.
• Decisions: GO:0080036 'regulation of cytokinin-activated signaling pathway' -> MODIFY to GO:0009736 (ARR1 is a pathway component). ISM cytoplasm/chloroplast removed; HDA cytosol over-annotated.
• Proposed NEW: GO:0001216 DNA-binding transcription activator activity (IDA, PMID:11135105).