Proteins containing a steroidogenic acute regulatory-related lipid transfer (START) domain are often involved in the trafficking of lipids and cholesterol between diverse intracellular membranes. This gene is a member of the StarD subfamily that encodes START-related lipid transfer proteins. The protein encoded by this gene is a cholesterol transporter and is also able to bind and transport other sterol-derived molecules related to the cholesterol/bile acid biosynthetic pathways such as 25-hydroxycholesterol. Its expression is upregulated during endoplasmic reticulum (ER) stress. The protein is thought to act as a cytosolic sterol transporter that moves cholesterol between intracellular membranes such as from the cytoplasm to the ER and from the ER to the Golgi apparatus. Alternative splicing of this gene produces multiple transcript variants. [provided by RefSeq, Jan 2016],