SLC5A1
Domain
The cholesterol-binding site is formed by transmembrane helices TM1, TM7 and TM13.
Function
Electrogenic Na(+)-coupled sugar symporter that actively transports D-glucose or D-galactose at the plasma membrane, with a Na(+) to sugar coupling ratio of 2:1. Transporter activity is driven by a transmembrane Na(+) electrochemical gradient set by the Na(+)/K(+) pump (PubMed:20980548, PubMed:34880492, PubMed:35077764, PubMed:8563765, PubMed:37217492). Has a primary role in the transport of dietary monosaccharides from enterocytes to blood. Responsible for the absorption of D-glucose or D-galactose across the apical brush-border membrane of enterocytes, whereas basolateral exit is provided by GLUT2. Additionally, functions as a D-glucose sensor in enteroendocrine cells, triggering the secretion of the incretins GCG and GIP that control food intake and energy homeostasis (By similarity) (PubMed:8563765). Together with SGLT2, functions in reabsorption of D-glucose from glomerular filtrate, playing a nonredundant role in the S3 segment of the proximal tubules (By similarity). Transports D-glucose into endometrial epithelial cells, controlling glycogen synthesis and nutritional support for the embryo as well as the decidual transformation of endometrium prior to conception (PubMed:28974690). Acts as a water channel enabling passive water transport across the plasma membrane in response to the osmotic gradient created upon sugar and Na(+) uptake. Has high water conductivity, comparable to aquaporins, and therefore is expected to play an important role in transepithelial water permeability, especially in the small intestine.
Involvement in disease
Congenital glucose/galactose malabsorption
GGM
Intestinal monosaccharide transporter deficiency. It is an autosomal recessive disorder manifesting itself within the first weeks of life. It is characterized by severe diarrhea and dehydration which are usually fatal unless glucose and galactose are eliminated from the diet.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
N-glycosylation is not necessary for the cotransporter function.
Sequence Similarities
Belongs to the sodium:solute symporter (SSF) (TC 2.A.21) family.
Tissue Specificity
Expressed in intestine (PubMed:2490366). Expressed in endometrial cells (PubMed:28974690).
Cellular localization
- Apical cell membrane
- Multi-pass membrane protein
Alternative names
NAGT, SGLT1, SLC5A1, Sodium/glucose cotransporter 1, Na(+)/glucose cotransporter 1, High affinity sodium-glucose cotransporter, Solute carrier family 5 member 1