LSR is a 649 amino acid single-pass membrane protein that contains one immunoglobulin-like domain and localizes to the cell membrane. Existing as a homotrimer or a homotetramer, LSR is thought to play a role in the clearing of triglyceride-rich lipoproteins from blood, specifically via binding to low density lipoproteins (LDLs) and very low density lipoproteins (VLDLs) and facilitating their uptake into cells. Overexpression of LSR may be associated with increased colon tumor growth, suggesting an involvement for LSR in tumor formation and metastasis. Multiple isoforms of LSR exist due to alternative splicing events. The gene encoding LSR maps to human chromosome 19, which consists of over 63 million bases, houses approximately 1,400 genes and is recognized for having the greatest gene density of the human chromosomes.