Growth factor involved in early embryonic development and adipose-tissue homeostasis. During embryogenesis controls formation of anterior visceral endoderm and mesoderm and the establishment of anterior-posterior identity through a receptor complex comprising the receptor ACVR1B and the coreceptor TDGF1/Cripto (PubMed:16368929, PubMed:17936261). Regulates adipose-tissue homeostasis and energy balance under nutrient overload in part by signaling through the receptor complex based on ACVR1C and TDGF1/Cripto. Homodimer. Heterodimer (Potential). But, in contrast to other members of this family, cannot be disulfide-linked. Mainly accumulated in the cytoplasm. Primarily in adult bone marrow, spleen, thymus and adipose tissue. Markedly increased in an obese-mouse model lacking adipocyte fatty acid-binding protein FABP4. Synthesized as large precursor molecule that undergo proteolytic cleavage, releasing the pro-domain from the active, receptor binding, C-terminal region of the molecule. Embryonic lethality in one-third of the mutant embryos because of pregastrulation developmental malformations. However, the majority of mutants survive until adulthood without any overt abnormality (PubMed:17936261, PubMed:16368929). Mutant mice shown resistance to diet-induced obesity (PubMed:18480259). In contrast to other members of this family, cannot be disulfide-linked due to an atypical cysteine knot configuration, where the fourth cysteine is missing. This fourth cysteine is involved in an inter-molecular bridge to stabilize the active form of homodimeric or heterodimeric signaling molecules. Belongs to the TGF-beta family.