GluLeuArg

GluLeuArg, written as Glu-Leu-Arg and commonly referred to as the ELR motif, is a specific tripeptide sequence composed of the amino acids glutamic acid (Glu), leucine (Leu), and arginine (Arg). In biochemistry, this motif is most notably found at the N-terminus of a subset of CXC chemokines.

The ELR motif serves as a key determinant of the chemokine’s biological activity. Chemokines bearing the Glu-Leu-Arg sequence typically exert pro-angiogenic effects and attract neutrophils by signaling through the CXCR1 and CXCR2 receptors on endothelial and immune cells. This motif enables these chemokines to stimulate blood vessel formation and neutrophil chemotaxis, processes that are important in wound healing and inflammatory responses.

Biological significance and diversity are linked to the presence or absence of the ELR motif. ELR-positive (ELR+) CXC chemokines promote angiogenesis, whereas ELR-negative (ELR−) members are generally associated with angiostasis. Examples of ELR+ chemokines include certain members of the CXCL1–CXCL8 family, such as CXCL1, CXCL2, CXCL3, CXCL5, and CXCL8 (interleukin-8). The ELR motif thus contributes to the functional specialization of the CXC chemokine subset and influences outcomes in inflammation, cancer, and tissue remodeling.

In research and clinical contexts, Glu-Leu-Arg is often discussed in relation to chemokine-receptor signaling, angiogenesis regulation, and neutrophil recruitment.