Question

During development, an environmental cue will cause stem cells to differentiate into a specific cell-type. A stem cell responds to the environmental change by producing and releasing a growth factor (GF). The GF binds to surface receptors on the same stem cell and initiate an intracellular signal transduction pathway. This is an example of ______ signaling. Ligands involved in this signaling are typically _____ (a molecular property)

Answer 1

The process described in the student's question is called autocrine signaling, where a cell responds to growth factors it releases, typically involving proteinaceous ligands and receptor tyrosine kinases.

Step-by-step explanation:

The environmental cue you mentioned causing stem cells to differentiate involves a type of signaling known as autocrine signaling. In autocrine signaling, the growth factor that a cell produces binds to receptors on the same cell, initiating a signal transduction pathway within itself. This mechanism is critical during the development of an organism to ensure that cells develop into the correct tissues and take on the proper functions. These growth factors are typically proteinaceous in nature. Autocrine signaling can also be involved in regulating pain, inflammation, and even programmed cell death.

Receptor tyrosine kinases (RTKs) are commonly involved in these pathways, and the signaling can lead to several outcomes like gene expression, cell division, and growth. When it comes to stem cell differentiation, the signals are precisely regulated to prevent unwanted outcomes like cancer, which can occur with uncontrolled cell growth due to inappropriate signaling. Thus, autocrine signaling ensures a balanced and targeted approach to cell development and differentiation.