LGR5

LGR5

Micrograph of the small intestine, where LGR5+ stem cells are found.

LGR5 (Leucine-rich repeat-containing G-protein coupled receptor 5) is a protein that in humans is encoded by the LGR5 gene. It is a member of the G-protein coupled receptor (GPCR) superfamily and is known for its role as a marker of adult stem cells in various tissues.

Function

LGR5 is primarily recognized for its role in identifying adult stem cells in the small intestine, colon, hair follicle, and other tissues. It is a receptor for R-spondins, which are proteins that potentiate Wnt signaling, a pathway crucial for stem cell maintenance and proliferation.

Expression

LGR5 is expressed in the crypt base columnar cells of the small intestine and colon, which are known to be stem cells responsible for the continuous renewal of the intestinal epithelium. In the hair follicle, LGR5 is expressed in the bulge region, which contains stem cells that contribute to hair growth and regeneration.

Role in Stem Cells

LGR5+ cells have been identified as multipotent stem cells capable of giving rise to all cell types within their respective tissues. In the intestine, LGR5+ stem cells are responsible for the rapid turnover of the intestinal lining, while in the hair follicle, they contribute to the cyclic regeneration of hair.

Diagram of a hair follicle, showing the location of LGR5+ stem cells in the bulge region.

Clinical Significance

LGR5 has been implicated in cancer research, as its expression is often upregulated in various cancers, including colorectal cancer. The presence of LGR5+ cells in tumors suggests a role in cancer stem cell biology, where these cells may contribute to tumor growth and resistance to therapy.

Research

Ongoing research is focused on understanding the precise mechanisms by which LGR5+ stem cells contribute to tissue homeostasis and regeneration, as well as their role in cancer. Targeting LGR5+ cells in cancer therapy is an area of active investigation, with the aim of developing treatments that can selectively eliminate cancer stem cells.

Related pages

• Wnt signaling pathway
• Stem cell
• G-protein coupled receptor
• Colorectal cancer