What cell types express high levels of GRAMD1C (G protein-coupled receptor-associated membrane protein domain-containing protein 1C)?

Cell Types That Express High Levels of GRAMD1C

Neutrophils and monocyte-derived cells express high levels of GRAMD1C, which functions as a cholesterol transport protein involved in autophagy regulation and immune cell function.

Primary Cell Types Expressing GRAMD1C

GRAMD1C (GRAM Domain Containing 1C) is a cholesterol transport protein that shows differential expression across various cell types. Based on the available evidence, the following cell types demonstrate significant GRAMD1C expression:

Myeloid-Derived Cells

• Neutrophils: Express high levels of GRAMD1C, particularly during inflammatory responses 1
• Monocyte-derived cells: Including:
  • Monocyte-derived dendritic cells (MDDCs)
  • Monocyte-derived macrophages
  • Myeloid-derived suppressor cells (MDSCs) 1

Other Immune Cells

• Regulatory T cells (Tregs): Show significant correlation with GRAMD1C expression 2
• Dendritic cells: Particularly conventional type 1 dendritic cells (cDC1s) 3

Functional Significance of GRAMD1C Expression

GRAMD1C plays several important roles in cellular function:

1. Autophagy Regulation:

   • Acts as a negative regulator of starvation-induced autophagy 4
   • Involved in autophagosome biogenesis at endoplasmic reticulum (ER)-associated sites 4

2. Cholesterol Transport:

   • Contains a StART domain that binds cholesterol 5
   • Facilitates cholesterol removal during autophagosome formation 4
   • Affects cholesterol distribution in response to cellular stress 5

3. Mitochondrial Bioenergetics:

   • Regulates mitochondrial function 4
   • May influence cellular metabolism in immune cells

Clinical Relevance

GRAMD1C expression has been linked to several clinical outcomes:

• Cancer Prognosis: Reduced GRAMD1C expression correlates with poor prognosis in kidney renal clear cell carcinoma (KIRC) 2
• Immune Infiltration: GRAMD1C expression levels correlate with tumor-infiltrating immune cells, particularly regulatory T cells 2
• Signaling Pathways: Associated with mTOR signaling, RNA degradation, WNT signaling, toll pathway, and AKT pathway in cancer 2

Experimental Considerations

When studying GRAMD1C expression:

• Cell-specific markers should be used alongside GRAMD1C detection to accurately identify expressing cell types
• Expression levels may vary based on activation state and inflammatory conditions
• Functional assays examining cholesterol transport and autophagy can help confirm the biological activity of GRAMD1C in identified cell populations

Understanding the cell type-specific expression of GRAMD1C provides insights into its role in immune function, autophagy regulation, and potential as a biomarker in various pathological conditions.