Pref1

Pref-1, also known as preadipocyte factor 1, is a protein encoded by the DLK1 gene (Delta-like 1 homolog) in humans. It is a transmembrane protein expressed in several tissues, most notably in preadipocytes and developing organs, and it exists in both membrane-bound and soluble forms produced by proteolytic cleavage.

Functionally, Pref-1 is a negative regulator of adipocyte differentiation. Its expression helps maintain precursor cells in a preadipocyte state and inhibits progression to mature adipocytes. The extracellular portion can be shed to generate a soluble Pref-1 fragment, which can act in nearby tissues to modulate adipogenesis and metabolic signaling. The protein contains extracellular epidermal growth factor-like repeats and a short cytoplasmic tail.

Genomic context and regulation: DLK1 is part of the imprinted DLK1-DIO3 locus on human chromosome 14 and is typically paternally expressed and maternally repressed in many tissues. DLK1 expression is observed during fetal development and in certain progenitor cell populations; its regulation involves imprinting controls and developmental cues.

Clinical relevance: Altered Pref-1/DLK1 expression has been linked to developmental and metabolic conditions. Higher Pref-1 levels are associated with inhibition of adipogenesis and can reflect fetal growth regulation, while lower levels favor adipocyte formation. DLK1 is also studied in cancer biology and stem cell research, and circulating Pref-1 has been explored as a biomarker in some contexts.