SDS

A cytokine that is part of the interleukin 6 family, Leukaemia inhibitory factor or LIF operates in the hypothalamus. Studies have shown that it may play a crucial role in energy homeostasis. The cytokine has also been found in the anterior pituitary and is able to trigger ACTH secretion in vitro and vivo, shown in studies on both mice and men. Indeed, studies have shown low plasma ACTH and damage HPA responses to immune stimuli or stress can both be corrected by LIF administration.

FunctionLIF gets its name from its power to induce terminal differentiation of myeloid leukemia cells. What this means is that LIF prevents their growth from continuing. You will also find certain other factors attributed to LIF such as influence on bone metabolism, embryogenesis, inflammation, and the growth promotion, as well as the differentiation of different groups of target cells. It is believed by some that LIF could help to improve the implantation rate in women who have experienced unexplained infertility. LIF has also been shown and indeed suggested as a possible alternate solution to feed cell culture. This is due to the limit that feeder cells actually only create LIF on the surface of the cells. Feeder cells that do not produce the LIF gene have been found not to effectively support stem cells. In contrast, LIF can effectively ensure self renewal. It is able to do this by gaining the activator of Stat3 and the signal transducer. Typically, LIF will be added to stem cell culture with the aim of reducing the chances of spontaneous differentiation.

StructureThe structure of LIF is made of main chain fold that conforms to the four a-helix bundle topology. This has been seen in various other members of the hematopoietic cytokine family. LIF is quite similar in terms of structure to both GH and granulocyte colony-stimulating factor. Studies and x-rays have also shown evidence for regions of conserved surface character.

InteractionsOver the years, studies have shown that LIF interacts with various other factors including the ciliary neurotrophic factor. The two share various common components through their multimeric receptors. The two cytokine receptors both contain gp190/low affinity LIF receptor and gp130/interleukin-60receptor transducer. Research has shown a mutual displacement toward the trimeric high-affinity CNTF receptor for LIF and CNTF. One study suggested that competition between the two factors is a result of three receptor components to establish a conformational site that is apparent for both LIF and CNTF.

MechanismsWhen LIF binds to the LIF receptor also known as LIFR-a, a heterodimer is formed. This has a specific subunit and that is apparent for all members of this particularly receptor family. The formation of the heterodimer than leads to the activation of JAK/STAT as well as MAPK. Typically, LIFe will be expressed in the trophectoderm of an embryo developing. The receptor, LIFR, is then expressed through the inner cell mass. Embryonic stem cells come from the inner cell mass during the blastocyst stage. As such, once they are removed, this also removes the LIF source.