Nucleostemin, serotonin and insulin signaling: controlling Drosophila growth

July 14, 2008

In the July 15th issue of G&D, Dr. Matthew Scott and colleagues at Stanford University School of Medicine reveal that a protein called Nucleostemin 3 links the serotonin and insulin signaling pathways in the control of Drosophila body size.

Nucleostemin proteins were originally identified in mammals, where they are associated with undifferentiated, proliferating stem cells. In human cells, Nucleostemin expression has been linked with certain types of cancer.

Initial work in the Scott lab into the developmental roles of Drosophila Nucleostemin proteins led the researchers towards a focus on the specific role of Nucleostemin 3 (NS3) in the regulation of growth and body size. The researchers found that NS3-deficient flies are about 60% smaller than normal, displaying both a reduced cell size and number, but having otherwise normal body proportions - a phenotype traditionally associated with defective insulin signaling.

Cell-specific NS3 disruption revealed that, although NS3 is expressed in several different cell types, it is required only in 106 serotonin-producing neurons to affect the overall organismal body size. Furthermore, the growth defect can be rescued by the introduction of NS3 expression into these serotonergic neurons.

Dr. Scott and colleagues demonstrated that within the fly brain, serotonergic neurons are situated in close proximity to insulin-producing cells, and thus suggest that NS3 functions in serotonergic neurons to influence insulin signaling and thereby regulate body size.

Dan Kaplan, a Stanford postdoctoral fellow working with Professors Scott and Tobias Meyer, is the first author of the study. He comments that "serotonin and insulin/insulin-like growth factor signaling mechanisms are evolutionarily conserved between flies and humans. We hope that our work in the fly will lead to new insights about the control of these pathways in humans, which could help us to understand, for example, how insulin signaling is mis-regulated in diabetes, or how insulin-like growth factor pathways are perturbed in developmental growth disorders or cancers."
-end-


Cold Spring Harbor Laboratory

Related Insulin Articles from Brightsurf:

US Insulin prices 8 times higher than in other nations
Insulin list prices in the United States have increased dramatically over the past decade, with per person insulin spending doubling between 2012 and 2016.

A gatekeeper against insulin resistance in the brain
The brain plays a major role in controlling our blood glucose levels.

Sorting and secreting insulin by expiration date
Visualizing the age of insulin secreting granules in cells allowed researchers to investigate how cells' preference for secreting newer granules is disrupted in diabetes.

Researchers develop a new ultrafast insulin
Stanford researchers tested a new insulin drug in diabetic pigs and found that it was twice as fast-acting as traditional insulin.

Insulin signaling suppressed by decoys
The discovery of an insulin 'decoy' molecule from the lab of Matthew Gill, PhD, in Florida shakes up understanding of insulin signaling, with implications for diabetes, longevity and aging research.

New mechanism for dysfunctional insulin release identified
In a new study, researchers at Uppsala University have identified a previously unknown mechanism that regulates release of insulin, a hormone that lowers blood glucose levels, from the β-cells (beta cells) of the pancreas.

Type 2 diabetes is not just about insulin
Obesity, by promoting the resistance to the action of insulin, is a major risk factor of diabetes.

The insulin under the influence of light
By understanding how the brain links the effects of insulin to light, researchers (UNIGE) are deciphering how insulin sensitivity fluctuates according to circadian cycles.

Does insulin resistance cause fibromyalgia?
Researchers led by a team from The University of Texas Medical Branch at Galveston were able to dramatically reduce the pain of fibromyalgia patients with medication that targeted insulin resistance.

Insulin insights
Insulin triggers genome-wide changes in gene expression via an unexpected mechanism.

Read More: Insulin News and Insulin Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.