Mutation of Ob (Obesity factor), also known as leptin precursor, results in profound obesity and type II diabetes as part of a syndrome that resembles morbid obesity in humans. The Ob gene product may function as a component of a signaling pathway in adipose tissue that functions to regulate body fat depot size. The leptin receptor, designated Ob-R, has been shown to be a single membrane-spanning receptor that most resembles the gp130 signal transducing component of the IL-6, G-CSF and LIF receptor. LEPROTL1 (Leptin receptor overlapping transcript-like 1) is a 131 amino acid multi-pass membrane protein that is highly homologous to the leptin receptor gene-related protein, Ob-R. LEPROTL1 is widely expressed and contains a JAK binding site. The LEPROTL1 gene is located on chromosome 8, which is made up of nearly 146 million bases and encodes about 800 genes.