SLC3A2

Developmental stage

Strong expression in the liver of 14 dpc embryo and in brain, spleen, liver, kidney and intestine of an 18 dpc embryo.

Function

Acts as a chaperone that facilitates biogenesis and trafficking of functional transporters heterodimers to the plasma membrane. Forms heterodimer with SLC7 family transporters (SLC7A5, SLC7A6, SLC7A7, SLC7A8, SLC7A10 and SLC7A11), a group of amino-acid antiporters (PubMed:10574970, PubMed:10734121, PubMed:11011012, PubMed:9915839). Heterodimers function as amino acids exchangers, the specificity of the substrate depending on the SLC7A subunit. Heterodimers SLC3A2/SLC7A6 or SLC3A2/SLC7A7 mediate the uptake of dibasic amino acids. Heterodimer SLC3A2/SLC7A11 functions as an antiporter by mediating the exchange of extracellular anionic L-cystine and intracellular L-glutamate across the cellular plasma membrane (By similarity). SLC3A2/SLC7A10 translocates small neutral L- and D-amino acids across the plasma membrane (By similarity). SLC3A2/SLC75 or SLC3A2/SLC7A8 translocates neutral amino acids with broad specificity, thyroid hormones and L-DOPA. SLC3A2 is essential for plasma membrane localization, stability, and the transport activity of SLC7A5 and SLC7A8. When associated with LAPTM4B, the heterodimer SLC7A5 is recruited to lysosomes to promote leucine uptake into these organelles, and thereby mediates mTORC1 activation. Modulates integrin-related signaling and is essential for integrin-dependent cell spreading, migration and tumor progression (By similarity).

Post-translational modifications

Phosphorylation on Ser-300 or Ser-302 and on Ser-420 by ecto-protein kinases favors heterotypic cell-cell interactions.

N-glycosylated; N-glycosylation is crucial for trafficking and stability of SLC3A2 to the plasma membrane.

Sequence similarities

Belongs to the SLC3A transporter family.

Tissue specificity

Detected on the surface of embryonic epithelial cells in the epidermis, thymus, kidney, intestine, brain choroid plexus, and in retina. Detected in adult and embryonic brain, spleen, kidney, intestine and liver, and in adult testis (at protein level) (PubMed:9915839). Observed in all adult tissues tested with strongest expression in kidney, small intestine, spleen, thymus and liver (PubMed:9915839). Moderate expression in brain, stomach, heart, testis, lung, skin, pancreas and skeletal muscle. In brain expressed on capillary endothelia in cerebral cortex.

Cellular localization

• Apical cell membrane
• Cell membrane
• Single-pass type II membrane protein
• Cell junction
• Lysosome membrane
• Melanosome
• Basolateral cell membrane
• Localized at the plasma membrane when associated with SLC7A5 or SLC7A8. Localized to the apical membrane of placental syncytiotrophoblastic cells. Recruited to lysosomes by LAPTM4B (By similarity). Located selectively at cell-cell adhesion sites (PubMed:9915839). Colocalized with SLC7A8/LAT2 at the basolateral membrane of kidney proximal tubules and small intestine epithelia. Expressed in both luminal and abluminal membranes of brain capillary endothelial cells (By similarity).

Alternative names

• Mdu1
• Mdu1
• Slc3a2
• Amino acid transporter heavy chain SLC3A2
• 4F2 cell-surface antigen heavy chain
• Solute carrier family 3 member 2
• 4F2hc

Database links

• swissprot:P10852

Target type

Proteins

Molecular weight

58337Da