SLC1A5 Gene

Overview

SLC1A5 (Solute Carrier Family 1 Member 5), also known as ASCT2 (Alanine-Serine-Cysteine Transporter 2), is a sodium-dependent neutral amino acid transporter critical for cellular uptake of glutamine, alanine, serine, and cysteine^{1Amino acid homeostasis and signalling in mammalian cells2017 · Biochem J · PMID 28437836Open reference}. ASCT2 is the primary glutamine transporter in the blood-brain barrier and plays essential roles in nitrogen metabolism, glutathione synthesis, and cellular signaling through the mTOR pathway. It is highly expressed in many cancers where it supports rapid glutamine metabolism^{2SLC transporters as therapeutic targets2020 · Nat Rev Drug Discov · PMID 32295719Open reference}.

The SLC1A5 gene is located on chromosome 19q13.33 and encodes a 541-amino acid protein with 10 transmembrane domains. Transport is driven by the Na+ gradient and couples the uptake of neutral amino acids to Na+ ion cotransport. ASCT2 is upregulated in many cancers and represents a therapeutic target for cancer treatment.

Evolutionary Conservation

SLC1 family transporters are evolutionarily conserved:

Tissue Distribution

Gene Information

Protein Overview

Molecular Function

Transport Properties

ASCT2 catalyzes Na+-dependent neutral amino acid exchange^{3The heteromeric amino acid transporter: structure, function, and disease2005 · Physiol Rev · PMID 15917204Open reference}:

1. Substrate specificity: Prefers glutamine, alanine, serine, cysteine

2. Ion coupling: 1 neutral AA + 1-2 Na+

3. Direction: Bidirectional (gradient-dependent)

4. pH optimum: pH 7.0-7.5

Substrate Profile

*Note: ASCT2 has very low affinity for glutamate; SLC1A2/A3 are glutamate-specific.

Cellular Functions

ASCT2 is critical for^{4Amino acid transporters in immunity2019 · Front Immunol · PMID 30867890Open reference}:

1. Glutamine uptake: Primary route for cellular glutamine

2. mTOR signaling: Glutamine activates mTORC1

3. Glutathione synthesis: Provides cysteine precursor

4. Immune function: Supports T-cell activation

5. Brain metabolism: Supplies glutamine to neurons

Role in Disease

Cancer Metabolism

ASCT2 is a major glutamine transporter in cancer^{5Glutamine metabolism in cancer2018 · Nat Rev Cancer · PMID 29393551Open reference}:

flowchart TD
    A["Cancer cell"] --> B["ASCT2 upregulation"]
    B --> C["Increased glutamine uptake"]
    C --> D["mTORC1 activation"]
    C --> E["Glutathione synthesis"]
    C --> F["Bioenergetics"]
    D --> G["Cell proliferation"]
    E --> H["Antioxidant defense"]
    F --> I["ATP production"]
    G --> J["Tumor growth"]

Neurodegeneration

ASCT2 dysfunction may contribute to^{6ASCT2 in neurodegenerative disease2019 · Neurobiol Dis · PMID 30609651Open reference}:

• Impaired brain glutamine supply

• Disrupted neurotransmitter cycling

• Altered glutathione metabolism

• mTOR dysregulation

Brain-Brain Barrier Function

ASCT2 is the primary glutamine transporter at the BBB^{7ASCT2 is the glutamine transporter in the blood-brain barrier2014 · J Cereb Blood Flow Metab · PMID 25121489Open reference}:

• Uptakes circulating glutamine into brain

• Partners with LAT1 (SLC7A5) for efflux

• Essential for glutamate-glutamine cycle

Genetics

Cancer-Associated Variants

Therapeutic Targeting

Structure

Protein Architecture

Interaction Network

flowchart TD
    subgraph Metabolism
    A["SLC1A5"] --> B["Glutamine pool"]
    A --> C["mTORC1"]
    A --> D["Glutathione"]
    end
    subgraph Transport
    A --> E["Na+ gradient"]
    A --> F["SLC7A5 (LAT1)"]
    end
    subgraph Disease
    A --> G["Cancer"]
    A --> H["Neurodegeneration"]
    end

Key Interacting Proteins

Clinical Relevance

Biomarker Potential

ASCT2 in Immunotherapy

ASCT2 is important for^{8Targeting glutamine transport in cancer2020 · Clin Cancer Res · PMID 32026558Open reference}:

• T-cell glutamine uptake

• Immune cell activation

• Checkpoint inhibitor response

See Also

• Solute Carrier Family

• Glutamine Metabolism

• Blood-Brain Barrier

• Cancer Metabolism

• mTOR Signaling