Seroatlas · Human Serome Atlas

MARCO

Macrophage receptor MARCO

Also known as: MARCO_HUMAN, SCARA2, SR-A6

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

Protein identityUniProt · HPA

UniProt accession: Q9UEW3
Gene: MARCO
Ensembl: ENSG00000019169
Chromosome: 2
Canonical length: 520 aa
Protein class: Plasma proteins, Predicted intracellular proteins, Predicted membrane proteins
Subcellular location: Golgi apparatus,Vesicles
Quaternary structure: Homotrimer

OverviewNCBI Gene

The protein encoded by this gene is a member of the class A scavenger receptor family and is part of the innate antimicrobial immune system. The protein may bind both Gram-negative and Gram-positive bacteria via an extracellular, C-terminal, scavenger receptor cysteine-rich (SRCR) domain. In addition to short cytoplasmic and transmembrane domains, there is an extracellular spacer domain and a long, extracellular collagenous domain. The protein may form a trimeric molecule by the association of the collagenous domains of three identical polypeptide chains. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

520 residues, UniProt reviewed canonical sequence.

>Q9UEW3|MARCO
     1  MRNKKILKED ELLSETQQAA FHQIAMEPFE INVPKPKRRN GVNFSLAVVV IYLILLTAGA
    61  GLLVVQVLNL QARLRVLEMY FLNDTLAAED SPSFSLLQSA HPGEHLAQGA SRLQVLQAQL
   121  TWVRVSHEHL LQRVDNFTQN PGMFRIKGEQ GAPGLQGHKG AMGMPGAPGP PGPPAEKGAK
   181  GAMGRDGATG PSGPQGPPGV KGEAGLQGPQ GAPGKQGATG TPGPQGEKGS KGDGGLIGPK
   241  GETGTKGEKG DLGLPGSKGD RGMKGDAGVM GPPGAQGSKG DFGRPGPPGL AGFPGAKGDQ
   301  GQPGLQGVPG PPGAVGHPGA KGEPGSAGSP GRAGLPGSPG SPGATGLKGS KGDTGLQGQQ
   361  GRKGESGVPG PAGVKGEQGS PGLAGPKGAP GQAGQKGDQG VKGSSGEQGV KGEKGERGEN
   421  SVSVRIVGSS NRGRAEVYYS GTWGTICDDE WQNSDAIVFC RMLGYSKGRA LYKVGAGTGQ
   481  IWLDNVQCRG TESTLWSCTK NSWGHHDCSH EEDAGVECSV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against MARCO 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: Cell surface
Secreted: No
Transmembrane segments: 1
Mean surface accessibility (rSASA): 0.61
Highest tissue expression: 188 nTPM

Expression across tissuesHPA

Tissue

lung: 188 nTPM
liver: 89 nTPM
appendix: 83 nTPM
adipose tissue: 61 nTPM
spleen: 37 nTPM
adrenal gland: 29 nTPM

Single-cell type

kupffer cells: 4,068 nCPM
hofbauer cells: 255 nCPM
macrophages: 253 nCPM
monocytes: 123 nCPM
cdc: 28 nCPM
epicardial cells: 16 nCPM

Immune cell

intermediate monocyte: 57 nTPM
classical monocyte: 34 nTPM
myeloid DC: 11 nTPM
total PBMC: 9.2 nTPM
non-classical monocyte: 7.3 nTPM
plasmacytoid DC: 1 nTPM

Brain region

thalamus: 28 nTPM
choroid plexus: 8.8 nTPM
cerebral cortex: 5.1 nTPM
pons: 3.8 nTPM
midbrain: 3.4 nTPM
basal ganglia: 2.5 nTPM

ReferencesPubMed · IEDB

Publications for MARCO from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Reference: AutoantibodyPubMed

4 publications

Autoantibody-mediated Macrophage Dysfunction in Patients with Severe Asthma with Airway Infections.
2023 · Am J Respir Crit Care Med · RCR 3.4 · 32 citations
Airway autoantibodies are determinants of asthma severity.
2022 · Eur Respir J · RCR 2.2 · 27 citations
Anti-class a scavenger receptor autoantibodies from systemic lupus erythematosus patients impair phagocytic clearance of apoptotic cells by macrophages in vitro.
2011 · Arthritis Res Ther · RCR 0.7 · 28 citations
Cutting Edge: Marginal Zone Macrophages Regulate Antigen Transport by B Cells to the Follicle in the Spleen via CD21.
2016 · J Immunol · RCR 0.5 · 19 citations

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

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): 1.34
gnomAD pLI: 0
gnomAD missense Z: -0.18
DepMap mean gene effect: -0.05
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

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

MARCO is annotated at the cell surface, where native MARCO is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

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

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