Plays a role in the regulation of lipogenesis, especially in lactating mammary gland. Important for the biosynthesis of triglycerides with medium-length fatty acid chains. May modulate lipogenesis by interacting with MID1IP1 and preventing its interaction with ACACA. May function as transcriptional coactivator. May modulate the transcription factor activity of THRB (By similarity). Homodimer. Heterodimer with MID1IP1. Interacts with THRB and PLAGL1 (By similarity). Mainly expressed in tissues that synthesize triglycerides. Decreased lipid synthesis in the lactating mammary gland. Milk has reduced triglyceride content, causing reduced weight gain in nursing pups. Adults exhibit reduced body fat content. No effect on lipid synthesis in liver. No effect on the expression of thyroid hormone-induced lipogenic genes. Belongs to the SPOT14 family.