Reviewed, UniProtKB/Swiss-Prot Q9BXJ7 (AMNLS_HUMAN)

Names and origin

Protein names

Recommended name:
    Amnionless protein

Gene names

Name:	AMN
ORF Names:	UNQ513/PRO1028

Organism

Homo sapiens (Human)

Taxonomic identifier

9606 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Primates › Haplorrhini › Catarrhini › Hominidae › Homo

Protein attributes

Sequence length	453 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Necessary for efficient absorption of vitamin B12. May direct the production of trunk mesoderm during development by modulating a bone morphogenetic protein (BMP) signaling pathway in the underlying visceral endoderm By similarity.
Subunit structure	Interacts with CUBN/cubilin.
Subcellular location	Membrane; Single-pass type I membrane proteinPotential.
Tissue specificity	Long isoforms are highly expressed in small intestine, colon and kidney (renal proximal tubule epithelial cells). Shorter isoforms are detected at lower levels in testis, thymus and peripheral blood leukocytes.
Involvement in disease	Defects in AMN are a cause of recessive hereditary megaloblastic anemia 1 (MGA1) [MIM:261100]; also referred to as MGA1 Norwegian type or Imerslund-Grasbeck syndrome (I-GS). MGA1 is due to selective malabsorption of vitamin B12. Defects in vitamin B12 absorption lead to impaired function of thymidine synthase. As a consequence DNA synthesis is interrupted. Rapidly dividing cells involved in erythropoiesis are particularly affected.
Miscellaneous	The mutations described in Ref.3 all affect the N-terminus of the protein; shorter isoforms produced from alternative transcription start sites might still fulfill a role in embryogenesis. This might explain the discrepancy with the embryonic lethality of null mutants in mice.
Sequence similarities	Contains 1 VWFC domain.

Ontologies

Keywords
Cellular component	Membrane
Coding sequence diversity	Alternative promoter usage
Disease	Disease mutation
Domain	Signal Transmembrane
Molecular function	Developmental protein
PTM	Glycoprotein
Technical term	Direct protein sequencing
Gene Ontology (GO)
None. [Check GOA]

Alternative products

This entry describes 1 isoform produced by alternative promoter usage. [Select]

Notes: At least 5 isoforms, 1, 2, 3, 4 and 5, are produced.

Isoform 1 (identifier: Q9BXJ7-1)

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view
Molecule processing
	Signal peptide	1 – 19	19	Potential
	Chain	20 – 453	434	Amnionless protein
Regions
	Topological domain	20 – 357	338	Extracellular Potential
	Transmembrane	358 – 378	21	Potential
	Topological domain	379 – 453	75	Cytoplasmic Potential
	Domain	202 – 254	53	VWFC
Amino acid modifications
	Glycosylation	35	1	N-linked (GlcNAc...) Potential
Natural variations
	Natural variant	41	1	T → I in MGA1.

Sequences

	Sequence		Length	Mass (Da)
	Isoform 1 [UniParc]. Last modified June 1, 2001. Version 1. Checksum: A1F2ABCE46649BFD	FASTA	453	47,815
	10 20 30 40 50 60 MGVLGRVLLW LQLCALTQAV SKLWVPNTDF DVAANWSQNR TPCAGGAVEF PADKMVSVLV 70 80 90 100 110 120 QEGHAVSDML LPLDGELVLA SGAGFGVSDV GSHLDCGAGE PAVFRDSDRF SWHDPHLWRS 130 140 150 160 170 180 GDEAPGLFFV DAERVPCRHD DVFFPPSASF RVGLGPGASP VRVRSISALG RTFTRDEDLA 190 200 210 220 230 240 VFLASRAGRL RFHGPGALSV GPEDCADPSG CVCGNAEAQP WICAALLQPL GGRCPQAACH 250 260 270 280 290 300 FALRPQGQCC DLCGAVVLLT HGPAFDLERY RARILDTFLG LPQYHGLQVA VSKVPRSSRL 310 320 330 340 350 360 READTEIQVV LVENGPETGG AGRLARALLA DVAENGEALG VLEATMRESG AHVWGSSAAG 370 380 390 400 410 420 LAGGVAAAVL LALLVLLVAP PLLRRAGRLR WRRHEAAAPA GAPLGFRNPV FDVTASEELP 430 440 450 LPRRLSLVPK AAADSTSHSY FVNPLFAGAE AEA

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"The amnionless gene, essential for mouse gastrulation, encodes a visceral-endoderm-specific protein with an extracellular cysteine-rich domain." Kalantry S., Manning S., Haub O., Tomihara-Newberger C., Lee H.-G., Fangman J., Disteche C.M., Manova K., Lacy E. Nat. Genet. 27:412-416(2001) [PubMed: 11279523] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA].
[2]	"The secreted protein discovery initiative (SPDI), a large-scale effort to identify novel human secreted and transmembrane proteins: a bioinformatics assessment." Clark H.F., Gurney A.L., Abaya E., Baker K., Baldwin D.T., Brush J., Chen J., Chow B., Chui C., Crowley C., Currell B., Deuel B., Dowd P., Eaton D., Foster J.S., Grimaldi C., Gu Q., Hass P.E. , Heldens S., Huang A., Kim H.S., Klimowski L., Jin Y., Johnson S., Lee J., Lewis L., Liao D., Mark M.R., Robbie E., Sanchez C., Schoenfeld J., Seshagiri S., Simmons L., Singh J., Smith V., Stinson J., Vagts A., Vandlen R.L., Watanabe C., Wieand D., Woods K., Xie M.-H., Yansura D.G., Yi S., Yu G., Yuan J., Zhang M., Zhang Z., Goddard A.D., Wood W.I., Godowski P.J., Gray A.M. Genome Res. 13:2265-2270(2003) [PubMed: 12975309] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] OF 1-230.
[3]	"Amnionless, essential for mouse gastrulation, is mutated in recessive hereditary megaloblastic anemia." Tanner S.M., Aminoff M., Wright F.A., Liyanarachchi S., Kuronen M., Saarinen A., Massika O., Mandel H., Broch H., de la Chapelle A. Nat. Genet. 33:426-429(2003) [PubMed: 12590260] [Abstract] Cited for: PROTEIN SEQUENCE OF 300-323 AND 393-453, TISSUE SPECIFICITY, VARIANT MGA1 ILE-41.
[4]	"The functional cobalamin (vitamin B12)-intrinsic factor receptor is a novel complex of cubilin and amnionless." Fyfe J.C., Madsen M., Hoejrup P., Christensen E.I., Tanner S.M., de la Chapelle A., He Q., Moestrup S.K. Blood 103:1573-1579(2004) [PubMed: 14576052] [Abstract] Cited for: IDENTIFICATION BY MASS SPECTROMETRY, INTERACTION WITH CUBN, TISSUE SPECIFICITY.
+	Additional computationally mapped references.

Web resources

GeneReviews

Cross-references

Sequence databases
EMBLGenBankDDBJ	AF328788 mRNA. Translation: AAK28532.1. AY358468 mRNA. Translation: AAQ89949.1.
UniGene	Hs.534494
3D structure databases
ModBase	Search...
Genome annotation databases
Ensembl	ENSG00000166126. Homo sapiens. [Contig view]
Organism-specific databases
H-InvDB	HIX0011994.
HGNC	HGNC:14604. AMN.
HPA	HPA000817.
MIM	261100. phenotype. 605799. gene.
Orphanet	35858. Graesbeck-Imerslund disease.
PharmGKB	PA134962814.
GenAtlas	Search...
GeneCards	Search...
Phylogenomic databases
HOGENOM	Q9BXJ7.
HOVERGEN	Q9BXJ7.
Gene expression databases
ArrayExpress	Q9BXJ7.
CleanEx	HS_AMN.
GermOnline	ENSG00000166126. Homo sapiens.
Family and domain databases
InterPro	IPR001007. VWF_C. [Graphical view]
PROSITE	PS01208. VWFC_1. False negative. PS50184. VWFC_2. False negative. [Graphical view]
ProDom	Q9BXJ7. [Graphical view] [Entries sharing at least one domain]
BLOCKS	Search...
Other Resources
DrugBank	DB00115. Cyanocobalamin. DB00200. Hydroxocobalamin.
SOURCE	Search...
ProtoNet	Search...

Entry information

Entry name

AMNLS_HUMAN

Accession

Primary (citable) accession number: Q9BXJ7
Secondary accession number(s): Q6UX83

Entry history

Integrated into UniProtKB/Swiss-Prot:	June 20, 2003
Last sequence update:	June 1, 2001
Last modified:	September 2, 2008
This is version 50 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HPI (Human Proteome Initiative)