SMIM11 (P58511) review notes

2026-10-03 Tier 2 microprotein review

Identity

• UniProt P58511 SIM11_HUMAN, 58 aa, PE1; aliases C21orf51, FAM165B, SMIM11A (HGNC:1293).
  Chromosome 21. N-terminal predicted helical TM segment (10-32) followed by a lysine-rich
  coiled-coil (29-58). Membrane / single-pass is curator inference (ECO:0000305).
• Family: Pfam PF14981 FAM165, InterPro IPR042125, PANTHER PTHR35975 (family name "SMALL INTEGRAL
  MEMBRANE PROTEIN 11A"). No characterized member.
• Expression: UniProt "Expressed in heart, spleen, liver, stomach, muscle, lung, testis, skin, PBL
  and bone marrow." HPA "Low tissue specificity". HPA antibody IF (proteinatlas.org JSON, fetched
  2026-10-03): "Focal adhesion sites". That is an unusual location for a single-pass peptide; it is not in GOA
  and not used.

Literature search

• PubMed SMIM11[tiab] OR C21orf51[tiab] OR FAM165B[tiab] OR SMIM11A[tiab] -> 2 hits.
• PMID:11707072 (Genomics 2001; abstract only): confirmation of C21orf51 as a bona fide transcript in a
  revision of the chromosome 21 transcription map PMID:11707072. Gene
  existence only.
• PMID:34113558 (sporamin-treated LoVo cells): lists "SMIM11A" among down-regulated "TFs". SMIM11 is
  not a transcription factor; this is a list-level mislabel and is not cited.

GOA rows

• 3 x protein binding (IPI), all HuRI PMID:32296183: ASPH isoform (Q12797-6), CERS4 (Q9HA82;
  ER-membrane ceramide synthase), UBQLN2 (Q9UHD9; cytosolic TMD chaperone
  PMID:27345149).
  CERS4 is a multi-pass ER-membrane enzyme; single Y2H hits between TM peptides and membrane proteins
  carry no functional information without follow-up. -> REMOVE all three.
• membrane (IEA) -> ACCEPT.

Conclusion

No function known. No core function, no NEW terms.