Seroatlas · Human Serome Atlas

SFI1

Protein SFI1 homolog

Also known as: KIAA0542, PISD, PPP1R139, SFI1_HUMAN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession: A8K8P3
Gene: SFI1
Ensembl: ENSG00000198089
Chromosome: 22
Canonical length: 1242 aa
Protein class: Predicted intracellular proteins

OverviewNCBI Gene

Enables phosphatase binding activity. Located in centriole. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

1242 residues, UniProt reviewed canonical sequence.

>A8K8P3|SFI1
     1  MKNLLTEKCI SSHNFHQKVI KQRMEKKVDS RYFKDGAVKK PYSAKTLSNK KSSASFGIRR
    61  ELPSTSHLVQ YRGTHTCTRQ GRLRELRIRC VARKFLYLWI RMTFGRVFPS KARFYYEQRL
   121  LRKVFEEWKE EWWVFQHEWK LCVRADCHYR YYLYNLMFQT WKTYVRQQQE MRNKYIRAEV
   181  HDAKQKMRQA WKSWLIYVVV RRTKLQMQTT ALEFRQRIIL RVWWSTWRQR LGQVRVSRAL
   241  HASALKHRAL SLQVQAWSQW REQLLYVQKE KQKVVSAVKH HQHWQKRRFL KAWLEYLQVR
   301  RVKRQQNEMA ERFHHVTVLQ IYFCDWQQAW ERRESLYAHH AQVEKLARKM ALRRAFTHWK
   361  HYMLLCAEEA AQFEMAEEHH RHSQLYFCFR ALKDNVTHAH LQQIRRNLAH QQHGVTLLHR
   421  FWNLWRSQIE QKKERELLPL LHAAWDHYRI ALLCKCIELW LQYTQKRRYK QLLQARADGH
   481  FQQRALPAAF HTWNRLWRWR HQENVLSARA TRFHRETLEK QVFSLWRQKM FQHRENRLAE
   541  RMAILHAERQ LLYRSWFMWH QQAAARHQEQ EWQTVACAHH RHGRLKKAFC LWRESAQGLR
   601  TERTGRVRAA EFHMAQLLRW AWSQWRECLA LRGAERQKLM RADLHHQHSV LHRALQAWVT
   661  YQGRVRSILR EVAARESQHN RQLLRGALRR WKENTMARVD EAKKTFQAST HYRRTICSKV
   721  LVQWREAVSV QMYYRQQEDC AIWEAQKVLD RGCLRTWFQR WWDCSRRSAQ QRLQLERAVQ
   781  HHHRQLLLEG LARWKTHHLQ CVRKRLLHRQ STQLLAQRLS RTCFRQWRQQ LAARRQEQRA
   841  TVRALWFWAF SLQAKVWATW LAFVLERRRK KARLQWALQA YQGQLLQEGA TRLLRFAASM
   901  KASRQQLQAQ QQVQAAHSLH RAVRRCATLW KQKVLGRGGK PQPLAAIAPS RKVTFEGPLL
   961  NRIAAGAGDG TLETKRPQAS RPLGALGRLA AEEPHALELN TAHSARKQPR RPHFLLEPAQ
  1021  SQRPQKPQEH GLGMAQPAAP SLTRPFLAEA PTALVPHSPL PGALSSAPGP KQPPTASTGP
  1081  ELLLLPLSSF MPCGAAAPAR VSAQRATPRD KPPVPSSLAS VPDPHLLLPG DFSATRAGPG
  1141  LSTAGSLDLE AELEEIQQQL LHYQTTKQNL WSCRRQASSL RRWLELNREE PGPEDQEVEQ
  1201  QVQKELEQVE MQIQLLAEEL QAQRQPIGAC VARIQALRQA LC

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SFI1 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability: Intracellular
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.55
Highest tissue expression: 26 nTPM

Expression across tissuesHPA

Tissue

cerebellum: 26 nTPM
bone marrow: 12 nTPM
lymph node: 11 nTPM
thymus: 9.9 nTPM
testis: 9.5 nTPM
pituitary gland: 9.4 nTPM

Single-cell type

endometrial luminal cells: 289 nCPM
retinal horizontal cells: 250 nCPM
epididymal principal cells: 165 nCPM
endometrial glandular cells: 164 nCPM
rod photoreceptor cells: 102 nCPM
sertoli cells: 91 nCPM

Immune cell

memory CD8 T-cell: 11 nTPM
naive CD4 T-cell: 9.9 nTPM
NK-cell: 9.4 nTPM
gdT-cell: 9.1 nTPM
naive CD8 T-cell: 8.9 nTPM
basophil: 8.5 nTPM

Brain region

cerebellum: 31 nTPM
cerebral cortex: 17 nTPM
choroid plexus: 17 nTPM
hypothalamus: 17 nTPM
medulla oblongata: 16 nTPM
basal ganglia: 16 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance): 1.01
gnomAD pLI: 0
gnomAD missense Z: -0.54
DepMap mean gene effect: -0.06
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Molecular functions

phosphatase binding

Cellular components

Protein domainsUniProt · Pfam · InterPro

Centrosome-associated contractile fiber protein

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of SFI1 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

CETN2

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SFI1 as an antibody target. Whether an autoantibody or antibody against SFI1 could matter depends on whether native SFI1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SFI1 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label SFI1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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