Notch Signaling: Developmental Regulation

As discussed before, Notch signaling is a form of cell communication that is a direct cell-to-cell interaction. It is the start of a signaling pathway in which from the outer membrane of a cell, a messenger is sent from one cell to the other’s nucleus area so that it can regulate a certain gene expression.

Notch signaling is a huge step in cell evolution. It became major component of our cell development to allow complex cell communication. It allowed neighboring cells to respond to both internal and external cues for development of the cells (Artavanis-Tsakonas, 1999). This adaptation would help cells survive in different situations and environments. It can be used in a defensive matter, but also as a developmental matter. As an organism develops into maturity, it has a stash of cells ready to become certain specialized cells. Notch signaling helps regulate the production of these specialized cells so the organism doesn’t have more than it needs (Lai, 2004). Without notch signaling, the organism never develops to maturity, but if it produces all the specialized cells at once, it loses the ability to express those cells later in its life. Notch signaling keeps a delicate balance for the organism to mature and function.

(A) showcases the goal for notch signaling, so that not all the cells are expressed at once. (B) shows when there is no notch at all, and when it signals to much. (D) (E) and (F) show what happens when notch is defective. (C) is a wild type organism.

This delicate balance is kept through a multiple different regulations of notch signaling. It can be regulated through methods like protein ligases interfering with endocytosis of signals, and the receptors being glycosylated, thus changing its ability to receive signals (Schweisguth, 2004). Carbohydrates are attached to the receptors, causing their shape to change. This limits its cell interaction on the outer membrane level. When this regulation goes awry, it can have lethal repercussions. It has been found that notch signaling can actually help tumors form and grow (Leong, 2006). When functioning, the notch signaling can help prevent growth by initiating apoptosis of the deadly cell.

Sources

Artavanis-Tsakonas, S. “Notch Signaling: Cell Fate Control and Signal Integration in Development.” Science 284.5415 (1999): 770-76.

Lai, E. C. “Notch Signaling: Control of Cell Communication and Cell Fate.” Development131.5 (2004): 965-73.

Schweisguth, François. “Regulation of Notch Signaling Activity.” Current Biology 14.3 (2004)

Leong, K. G. “Recent Insights into the Role of Notch Signaling in Tumorigenesis.” Blood107.6 (2006): 2223-233.