What is the role of activin and nodal for directing Endodermal differentiation?

Activin/Nodal signaling is necessary to maintain pluripotency of human embryonic stem cells (hESCs) and to induce their differentiation toward endoderm. However, the mechanisms by which Activin/Nodal signaling achieves these opposite functions remain unclear.

What is Nodal and Activin?

Nodal and Activin ligands can both signal through the same receptors and effectors in order to regulate transcription. In many cases, the effects of Nodal and Activin-mediated signalling are indistinguishable; hence, they are referred to as the Activin/Nodal pathway.

What is cell pluripotency?

Pluripotent stem cells are cells that have the capacity to self-renew by dividing and to develop into the three primary germ cell layers of the early embryo and therefore into all cells of the adult body, but not extra-embryonic tissues such as the placenta.

What is the significance of pluripotent stem cells?

First, by their nature, pluripotent stem cells can potentially be used to create any cell or tissue the body might need to counter a wide range of diseases, from diabetes to spinal cord injury, to childhood leukemia, to heart disease.

Is nodal a BMP?

Nodal and BMP signal non-cell-autonomously and form similar protein gradients in this context, but the signaling range of Nodal (pSmad2) is shorter than the BMP range (pSmad5).

What are nodal functions?

Nodal is a secretory protein that in humans is encoded by the NODAL gene which is located on chromosome 10q22.1. In addition, Nodal seems to have important functions in neural patterning, stem cell maintenance and many other developmental processes, including left/right handedness.

What is Totipotency of cell?

A totipotent cell is a single cell that can give rise to a new organism, given appropriate maternal support (most stringent definition) A totipotent cell is one that can give rise to all extraembryonic tissues, plus all tissues of the body and the germline (less stringent definition)

What type of cells are pluripotent?

Pluripotent cells can give rise to all of the cell types that make up the body; embryonic stem cells are considered pluripotent. Multipotent cells can develop into more than one cell type, but are more limited than pluripotent cells; adult stem cells and cord blood stem cells are considered multipotent.

What can pluripotent cells not become?

Totipotent stem cells can divide into all cell types in an organism. A totipotent cell has the potential to divide until it creates an entire, complete organism. Pluripotent stem cells can divide into most, or all, cell types in an organism, but cannot develop into an entire organism on their own.

What are the properties of pluripotent cells?

The definition of pluripotent stem cell is based on two properties: self-renewal and potency. The self-renewal is the capacity of the stem cells to divide indefinitely, producing unaltered cell daughters maintaining the same properties of the progenitor cell.

Is nodal a transcription factor?

NODAL is a member of the TGFβ family of developmental regulators. NODAL, LEFTY1/LEFTY2, and GDF1 act as ligands for a membrane multisubunit receptor composed of ACVR1B/ACVR2A/ACVR2B, CFC1, and TDGF1, which controls, through transcription factors, such as FOXH1 and ZIC3, cardiac-specific effector genes.

Is Smad a transcription factor?

The eight members of the Smad family are divided among these three groups. Trimers of two receptor-regulated SMADs and one co-SMAD act as transcription factors that regulate the expression of certain genes.