Acts as a feedback negative regulator of signaling by receptor tyrosine kinases, through a mechanism that involves enhancement of receptor ubiquitination and accelerated intracellular degradation. Interacts (via extracellular LRR and Ig-like domains) with EGFR/ERBB1, ERBB2, ERBB3 and ERBB4 (via extracellular domain). The physiological relevance of the interaction is controversial; LRIG1 may have low affinity for EGFR, and interaction may occur only when high levels of both proteins are present. Detected in brain (at protein level) (PubMed:12067728). Predominantly expressed in the brain, restricted to a small subset of glial cells, such as Bergmann glial cells of the cerebellum and glial cells in the nerve fiber layer of the olfactory bulb. Expressed also in the skin. Low expression is detected in the thymus and heart. No expression in the kidney, liver, lung or small intestine. Contains LRR and Ig-domains that can mediate low-affinity interaction with EGFR. The LRRs and the Ig-domains are each sufficient for EGFR/ERBB1 binding. This interaction is abolished only when both the LRRs and the Ig-domains are deleted. Mutant mice are born at the expected Mendelian rate and initially display no visible phenotype. One to four months after birth, they develop skin abnormalities including alopecia and epidermal hyperplasia that are reminiscent of psoriasis.