Seroatlas · Human Serome Atlas

LLCFC1

Sperm-egg fusion protein LLCFC1

Also known as: C7orf34, CTM-1, LCFC1_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q96L11
Gene: LLCFC1
Ensembl: ENSG00000165131
Chromosome: 7
Canonical length: 122 aa
Protein class: Predicted intracellular proteins, Predicted secreted proteins
Secretome location: Secreted in male reproductive system

OverviewNCBI Gene

Predicted to be involved in fusion of sperm to egg plasma membrane involved in single fertilization. Predicted to be located in extracellular region. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

122 residues, UniProt reviewed canonical sequence.

>Q96L11|LLCFC1
     1  MPPLAPQLCR AVFLVPILLL LQVKPLNGSP GPKDGSQTEK TPSADQNQEQ FEEHFVASSV
    61  GEMWQVVDMA QQEEDQSSKT AAVHKHSFHL SFCFSLASVM VFSGGPLRRT FPNIQLCFML
   121  TH

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against LLCFC1 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: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.59
Highest tissue expression: 61 nTPM

Expression across tissuesHPA

Tissue

testis: 61 nTPM
bone marrow: 1.5 nTPM
spinal cord: 1.3 nTPM
spleen: 1.1 nTPM
midbrain: 0.5 nTPM
prostate: 0.4 nTPM

Single-cell type

early spermatids: 11 nCPM
late spermatids: 6.4 nCPM
late primary spermatocytes: 4 nCPM
oligodendrocytes: 0.2 nCPM
leydig cells: 0.1 nCPM
renal collecting duct intercalated cells: 0.1 nCPM

Immune cell

neutrophil: 0.1 nTPM
basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM
intermediate monocyte: 0 nTPM

Brain region

white matter: 18 nTPM
medulla oblongata: 17 nTPM
pons: 11 nTPM
basal ganglia: 9.9 nTPM
midbrain: 9.5 nTPM
thalamus: 9.3 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): 1.87
gnomAD pLI: 0
DepMap mean gene effect: -0.07
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

Biological processes

fusion of sperm to egg plasma membrane involved in single fertilization

Cellular components

extracellular region

Protein domainsUniProt · Pfam · InterPro

Sperm-egg fusion protein LLCFC1
LLLL and CFNLAS motif-containing protein 1

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads LLCFC1 as an antibody target. Whether an autoantibody or antibody against LLCFC1 could matter depends on whether native LLCFC1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

LLCFC1 is annotated as secreted, so native LLCFC1 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label LLCFC1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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