Human Leucine-Rich Repeats and Immunoglobulin-Like Domains Protein 1 (LRIG1) Protein

Background

LRIG1 is a transmembrane protein characterized by leucine-rich repeats (LRRs) and immunoglobulin-like (Ig-like) domains, which mediate protein-protein interactions. LRIG1 is expressed in various tissues and plays a critical role in regulating cell growth, differentiation, and signaling pathways, particularly in epidermal and neural cells. LRIG1 acts as a negative regulator of receptor tyrosine kinases (RTKs), such as EGFR (epidermal growth factor receptor), by promoting their degradation. LRIG1 maintains stem cell homeostasis in epithelial tissues, such as the skin and intestines. Dysregulation of LRIG1 expression is linked to cancer progression, where its loss contributes to unchecked cell proliferation and metastasis. Conversely, high LRIG1 levels correlate with better prognosis in certain cancers. LRIG1 also regulates neuronal signaling and plasticity, highlighting its broad functional importance in both development and disease.