Competing proteins influence strength of tooth enamel

September 01, 2005

A gene critical to tooth formation expresses a protein that is then cleaved into two proteins with seemingly opposite functions, according to a USC-led team of dental researchers.

The team's study of the two proteins, dentin sialoprotein (DSP) and dentin phosphoprotein (DPP), has been accepted by the Journal of Biological Chemistry and is available on the journal's Website.

Lead author Michael Paine of the USC School of Dentistry said both proteins derive from the gene for dentin sialophosphoprotein, which plays an important role in the formation of the tooth coverings enamel and its softer internal cousin dentin.

"We were able to dissect this gene into two different proteins and look at them individually," Paine said.

The researchers conducted animal studies in which either DSP or DPP were over-expressed in forming enamel during the period of tooth development. They found that over-expression of DSP increased the hardness of enamel and its rate of formation, while over-expression of DPP created pitted and chalky enamel that was more prone to fracture and wear.

In normal teeth, DSP is expressed only in dentin and a very thin layer of enamel at the junction with dentin. This thin enamel layer also appears to be considerably harder than the bulk enamel of teeth, Paine said. He suggested that DSP could have the potential to become a protective agent in dental care.

If the protein could be incorporated into the entire layer of enamel, Paine said, "then it might act in a similar way to fluoride in water" by making teeth harder and more resistant to decay.

Paine cautioned that, just as heavy fluoridation can weaken teeth, excessive expression of DSP could be detrimental.

"There might be a point where if you increase the hardness anymore, teeth might be too brittle."

While the other protein, DPP, appears to weaken enamel, it too is necessary for proper tooth formation.

"All the data suggests that it [DPP] is one of the few proteins that seems to be involved with the very early stages of mineralization," Paine said.

The fine balance between DSP and DPP highlights the delicacy of the critical dentin-enamel junction, where the softer dentin is joined securely to the outer, ceramic-like enamel covering.

Dental researchers sometimes liken dentin and enamel to a bed mattress and a glass plate, respectively, Paine said, with the difference that the supple dentin-enamel junction prevents the enamel from shattering over an individual's lifetime of chewing and grinding.

The study built on the work of co-author Mary MacDougall, a former USC researcher who in 1997 was the first to show that DSP and DPP came from the same gene.
-end-
This research was supported by the National Institute of Dental and Craniofacial Research.

University of Southern California

Related Proteins Articles from Brightsurf:

New understanding of how proteins operate
A ground-breaking discovery by Centenary Institute scientists has provided new understanding as to the nature of proteins and how they exist and operate in the human body.

Finding a handle to bag the right proteins
A method that lights up tags attached to selected proteins can help to purify the proteins from a mixed protein pool.

Designing vaccines from artificial proteins
EPFL scientists have developed a new computational approach to create artificial proteins, which showed promising results in vivo as functional vaccines.

New method to monitor Alzheimer's proteins
IBS-CINAP research team has reported a new method to identify the aggregation state of amyloid beta (Aβ) proteins in solution.

Composing new proteins with artificial intelligence
Scientists have long studied how to improve proteins or design new ones.

Hero proteins are here to save other proteins
Researchers at the University of Tokyo have discovered a new group of proteins, remarkable for their unusual shape and abilities to protect against protein clumps associated with neurodegenerative diseases in lab experiments.

Designer proteins
David Baker, Professor of Biochemistry at the University of Washington to speak at the AAAS 2020 session, 'Synthetic Biology: Digital Design of Living Systems.' Prof.

Gone fishin' -- for proteins
Casting lines into human cells to snag proteins, a team of Montreal researchers has solved a 20-year-old mystery of cell biology.

Coupled proteins
Researchers from Heidelberg University and Sendai University in Japan used new biotechnological methods to study how human cells react to and further process external signals.

Understanding the power of honey through its proteins
Honey is a culinary staple that can be found in kitchens around the world.

Read More: Proteins News and Proteins 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.