positive regulation of L-leucine import across plasma membrane

Definition

Target type: biologicalprocess

Any process that activates or increases the frequency, rate or extent of L-leucine import across plasma membrane. [GO_REF:0000058, GOC:TermGenie, PMID:10467003]

The biological process of positive regulation of L-leucine import across the plasma membrane involves a complex interplay of transporters, signaling pathways, and cellular mechanisms.

**1. Transporter Proteins:**
- **SLC7A5 (LAT1):** This is a primary transporter responsible for the uptake of branched-chain amino acids (BCAAs), including L-leucine, across the plasma membrane. LAT1 requires the presence of a co-transporter, SLC3A2 (4F2hc), for its proper function.
- **SLC38A2 (SNAT2):** This transporter is responsible for the uptake of L-leucine via system A transport. This system is sodium-dependent and is primarily responsible for the uptake of neutral amino acids, including L-leucine, from the blood into cells.

**2. Signaling Pathways:**
- **mTORC1 Pathway:** The mammalian target of rapamycin complex 1 (mTORC1) is a key regulator of cell growth and metabolism. It plays a critical role in regulating the expression and activity of both LAT1 and SNAT2.
- When amino acid levels are high, mTORC1 is activated, leading to increased transcription of genes involved in amino acid transport, including LAT1 and SNAT2.
- This increased expression enhances L-leucine uptake into cells.
- **Insulin Signaling Pathway:** Insulin, a key regulator of glucose metabolism, also plays a role in L-leucine transport.
- Insulin stimulation can activate mTORC1, leading to increased L-leucine uptake through the activation of LAT1 and SNAT2.
- **Amino Acid Sensing Mechanisms:**
- Cells possess mechanisms to sense intracellular amino acid concentrations. When L-leucine levels are low, this triggers a signaling cascade that increases the activity of the transporters.
- This mechanism ensures that cells can maintain sufficient levels of L-leucine for protein synthesis and other cellular functions.

**3. Cellular Processes:**
- **Protein Synthesis:** L-leucine is an essential amino acid required for protein synthesis. Increased L-leucine import is crucial for supporting protein synthesis during cell growth and development.
- **Energy Metabolism:** L-leucine can be utilized as a source of energy in some tissues. Increased L-leucine uptake can contribute to energy production when other energy sources are limited.
- **Cell Signaling:** L-leucine is involved in various cell signaling pathways, including mTORC1, that regulate cellular processes such as growth, proliferation, and metabolism.

**4. Regulation of L-leucine Import:**
- **Transcriptional regulation:** Transcription factors, like the transcription factor CHOP (CCAAT/enhancer-binding protein homologous protein) and others, can regulate the transcription of LAT1 and SNAT2 genes, influencing the overall availability of these transporters.
- **Post-translational modifications:** Phosphorylation of LAT1 and SNAT2 can affect their activity. These modifications can be triggered by signaling pathways like mTORC1, insulin signaling, and others.
- **Cellular localization:** The distribution of LAT1 and SNAT2 within the plasma membrane can be influenced by various factors, impacting the efficiency of L-leucine import.

The precise mechanisms and relative contributions of these different aspects may vary depending on the specific cell type and physiological context. However, the coordinated action of these transporters, signaling pathways, and cellular processes ensures efficient L-leucine import across the plasma membrane, contributing to essential cellular functions.'"

Proteins (1)

Compounds (19)