SMAP1 (stromal membrane-associated protein 1)

2008-03-01 Kenji Tanabe , Shunsuke Kon , Masanobu Satake Affiliation

Department of Molecular Immunology, Institute of Development, Aging,, Cancer, Tohoku University, Sendai, Japan

Identity

HGNC

SMAP1

LOCATION

6q13

LOCUSID

60682

ALIAS

SMAP-1

FUSION GENES

Show Gene Fusions

DNA/RNA

Description

The gene spans an approximately 190 kb region, and is composed of 11 exons.

Transcription

There is only one transcription initiation site. However, due to alternative splicing, generated are two types of transcripts, isoforms A and B. The length of each transcript is either 3344 (isoform A) or 3263 nt (isoform B). The isoform A retains, and the isoform B lacks in-flame exon 5, respectively.

Proteins

Note

SMAP1 is a member in the ArfGAP protein family.

GAP, an ArfGAP domain; K-rich, a lysine-rich region; CHC, a clathrin heavy chain-binding motif; CALM, a clathrin assembly protein (CALM)-binding domain.

Description

There are two isoform proteins. One translated from an isoform A transcript is constituted by 467, and the other from an isoform B is by 440 aa residues. A protein diagram shown above represents an isoform B type.

Expression

Both isoform transcripts are detected in various human tissues. Expression appears to be almost ubiquitous.

Localisation

SMAP1 protein is detected in the cytoplasm of cells, and appears to be highly concentrated near the plasma membrane.

Function

SMAP1 functions as a GTPase-activating protein for an Arf6 GTPase. Arf6 is a Ras-related, small GTPase, and regulates clathrin-dependent and -independent endocytosis as well as actin dynamics. SMAP1 is specifically involved in the Arf6-regulated, clathrin-dependent endocytosis. This is achieved by direct interaction of SMAP1 with clathrin heavy chain.

Homology

As a highly homologous gene to SMAP1, SMAP2 is identified on 1p34.1-35.3. SMAP1 and SMAP2 constitute a small subfamily in the ArfGAP family. SMAP2 protein is specifically involved in the early endosomes to trans-Golgi network transport.

Implicated in

Entity name

t(6;11)(q13;q23) in acute leukemia.

Note

Two cases have been reported so far.

Disease

One case is from an M4 subtype of acute myeloid leukemia. A type of leukemia is not described for the other case.

Hybrid gene

One leukemia patient possessed the 46, XX, t(6;11)(q13;q23) karyotype. In this patient, reciprocal translocation occured between intron 11 of MLL gene and intron 6 of SMAP1 gene. The chimeric 5-MLL-SMAP1-3 transcript encodes a chimeric MLL-SMAP1 protein.

Fusion protein

MLL-SMAP1

Schematic illustration of chimeric MLL-SMAP1 protein. The authentic MLL and SMAP1 proteins are also shown.

AT hook, an AT-hook domain; NLS, a nuclear localization signal; MT, a methyltransferase domain; PHD, a plant homeodomain zinc finger; BROMO, a bromo domain; SET, a su(var)3-9, enhancer-of-zeste, trithorax domain. GAP, an ArfGAP domain; K-rich, a lysine-rich region; CHC, a clathrin heavy chain-binding motif; CALM, a clathrin assembly protein (CALM)-binding domain.

Article Bibliography

Pubmed ID	Last Year	Title	Authors
9593286	1998	Ten novel 11q23 chromosomal partner sites. European 11q23 Workshop participants.	Harrison CJ et al
12119110	2002	Cloning, characterization and chromosome mapping of the human SMAP1 gene.	Marcos I et al
15626757	2005	Diagnostic tool for the identification of MLL rearrangements including unknown partner genes.	Meyer C et al
16571680	2006	SMAP2, a novel ARF GTPase-activating protein, interacts with clathrin and clathrin assembly protein and functions on the AP-1-positive early endosome/trans-Golgi network.	Natsume W et al
16805823	2006	Involvement of a novel ADP-ribosylation factor GTPase-activating protein, SMAP, in membrane trafficking: implications in cancer cell biology.	Tanabe K et al
15659652	2005	A novel GTPase-activating protein for ARF6 directly interacts with clathrin and regulates clathrin-dependent endocytosis.	Tanabe K et al

Other Information

Locus ID:

NCBI: 60682
MIM: 611372
HGNC: 19651
Ensembl: ENSG00000112305

Variants:

dbSNP: 60682
ClinVar: 60682
TCGA: ENSG00000112305
COSMIC: SMAP1

RNA/Proteins

Gene ID	Transcript ID	Uniprot
ENSG00000112305	ENST00000316999	Q8IYB5
ENSG00000112305	ENST00000370452	Q8IYB5
ENSG00000112305	ENST00000370455	Q8IYB5
ENSG00000112305	ENST00000439432	H0Y5G0
ENSG00000112305	ENST00000445046	Q5T6I8
ENSG00000112305	ENST00000619054	A0A087X1X9

Expression (GTEx)

Adipose - Subcutaneous

Adipose - Visceral

Adrenal Gland

Artery - Aorta

Artery - Tibial

Bladder

Brain - Amygdala

Brain - Anterior cingulate cortex

Brain - Caudate

Brain - Cerebellar Hemisphere

Brain - Cerebellum

Brain - Cortex

Brain - Frontal Cortex

Brain - Hippocampus

Brain - Hypothalamus

Brain - Nucleus accumbens

Brain - Putamen

Brain - Spinal cord

Brain - Substantia nigra

Breast - Mammary Tissue

Cells - Cultured fibroblasts

Cells - EBV - transformed lymphocytes

Cervix - Ectocervix

Cervix - Endocervix

Colon - Sigmoid

Colon - Transverse

Esophagus - Gastroesophageal Junction

Esophagus - Mucosa

Esophagus - Muscularis

Fallopian Tube

Heart - Atrial Appendage

Heart - Left Ventricle

Kidney - Cortex

Kidney - Medulla

Liver

Lung

Minor Salivary Gland

Muscle - Skeletal

Nerve - Tibial

Ovary

Pancreas

Pituitary

Prostate

Skin - Not Sun Exposed

Skin - Sun Exposed

Small Intestine - Terminal Ileum

Spleen

Stomach

Testis

Thyroid

Uterus

Vagina

Whole Blood

Pathways

Pathway	Source	External ID
Endocytosis	KEGG	ko04144
Endocytosis	KEGG	hsa04144

Protein levels (Protein atlas)

Not detected

Low

Medium

High

References

Pubmed ID	Year	Title	Citations
36494580	2023	Pals1 functions in redundancy with SMAP1 to inhibit Arf6 in order to prevent Rac1-dependent colorectal cancer cell migration and invasion.	0
36494580	2023	Pals1 functions in redundancy with SMAP1 to inhibit Arf6 in order to prevent Rac1-dependent colorectal cancer cell migration and invasion.	0
28011674	2017	Rare genetic variants in SMAP1, B3GAT2, and RIMS1 contribute to pediatric venous thromboembolism.	8
28011674	2017	Rare genetic variants in SMAP1, B3GAT2, and RIMS1 contribute to pediatric venous thromboembolism.	8
23752192	2014	Involvement of small ArfGAP1 (SMAP1), a novel Arf6-specific GTPase-activating protein, in microsatellite instability oncogenesis.	0
25281535	2014	The Arf GTPase-activating protein SMAP1 promotes transferrin receptor endocytosis and interacts with SMAP2.	6
23752192	2014	Involvement of small ArfGAP1 (SMAP1), a novel Arf6-specific GTPase-activating protein, in microsatellite instability oncogenesis.	0
25281535	2014	The Arf GTPase-activating protein SMAP1 promotes transferrin receptor endocytosis and interacts with SMAP2.	6
15659652	2005	A novel GTPase-activating protein for ARF6 directly interacts with clathrin and regulates clathrin-dependent endocytosis.	32
15659652	2005	A novel GTPase-activating protein for ARF6 directly interacts with clathrin and regulates clathrin-dependent endocytosis.	32

Citation

Kenji Tanabe ; Shunsuke Kon ; Masanobu Satake

SMAP1 (stromal membrane-associated protein 1)

Atlas Genet Cytogenet Oncol Haematol. 2008-03-01

Online version: http://atlasgeneticsoncology.org/gene/42974/smap1