May regulate the number of excitatory synapses that are formed on hippocampus neurons. Has no effect on inhibitory synapses (By similarity). Plays a role in glucose homeostasis. Via AMPK signaling pathway, stimulates glucose uptake in adipocytes, myotubes and hepatocytes and enhances insulin-stimulated glucose uptake. In a hepatoma cell line, reduces the expression of gluconeogenic enzymes G6PC1 and PCK1 and hence decreases de novo glucose production (By similarity). Forms homooligomers. Interacts with ADGRB3. Interacts with C1QL2 and C1QL4, when proteins are coexpressed; this interaction does not occur after secretion. Highly expressed in adipose tissue, with expression levels at least 2 orders of magnitude higher than in other tissues, including brain and kidney.