ICE1 / SCRM (At3g26744, Q9LSE2) curation notes

Session 2026-10-06 (stomatal_lineage_development module). The initial just fetch-gene ARATH ICE1 retrieved an unreviewed TrEMBL entry (A0A1I9LRH4, an alternative gene model); folder was deleted and refetched by accession (Q9LSE2 --alias ICE1). UniProt primary name is SCRM; gene_symbol set to ICE1 (TAIR symbol, folder name). Falcon deep research failed (HTTP 402).

Key findings

• SCRM = ICE1; SCRM/SCRM2 heterodimerize with SPCH, MUTE, FAMA; scrm scrm2 successively phenocopies fama, mute, spch; scrm-D (R236H) gives stomata-only epidermis PMID:18641265.
• SCRM scaffolds MPK3/6 to SPCH through a bipartite MAPK-docking + KRAAM (KiDoK) motif; scrm-D abolishes MPK3/6 binding PMID:31235876.
• Cold: ICE1 binds MYC sites in CBF3 promoter and is a transcriptional activator, constitutively expressed PMID:12672693; HOS1 ubiquitinates PMID:16702557; SIZ1 sumoylates (K393) PMID:17416732.
• DISPUTE: ice1-1 DREB1A/CBF3 repression is transgene-induced silencing; ICE1 OE or ice1 scrm2 loss did not alter DREB1A PMID:32034036; rebuttal with ICE1 ChIP-seq at CBF/COR promoters PMID:32068336.
• Seeds: ICE1 with ZOU controls endosperm and dormancy; represses ABI3 PMID:30570804; antagonizes ABI5/DELLA in germination PMID:31123050.

Curation decisions

• Core MFs: protein heterodimerization activity (NEW; SPCH protein binding MODIFIED), DNA-binding TF activity (accepted), protein-macromolecule adaptor activity (NEW, IDA PMID:31235876). Core BP: stomatal lineage progression.
• Cold-related: response to cold IEP MARK_AS_OVER_ANNOTATED (gene constitutively expressed; role disputed); response to freezing KEEP_AS_NON_CORE with dispute noted.
• Generic protein binding rows (HOS1 x2, MYB15, MYC67/70, ABI5/DELLAs, LFR) REMOVED.
• No GO-CAM models contain ICE1.