New protein a key to cell shape and movement

August 06, 2000

A protein discovered by scientists at the University of North Carolina at Chapel Hill appears to play a key role in determining the shape of cells and allowing them to move.

The newly identified protein, palladin, is being explored for its influence on a number of biological processes including the invasive spread of cancer, wound healing, brain development, and the implantation of the embryo in the uterus.

"I think it may be critically involved in even more biological functions," said Carol A. Otey, PhD, assistant professor of cell and molecular physiology at UNC-CH School of Medicine.

A report of the discovery, co-authored by Mana M. Parast, PhD, of the University of Virginia, will be published in the August 7 issue on the Journal of Cell Biology.

Otey named the new protein after Andrea Palladio, the influential 16th century architect. Palladin appears to be very involved in the architecture of cells, specifically via the actin cytoskeleton, a polymer protein complex that provides much of the basis for cell shape.

"Cells have a shape that is related to their function," Otey explains. "A good example of specialized cell shape is the neuron. They must be very long and skinny to allow the nervous system to function. Another example is epithelial cells [including skin cells] which bind tightly to one another to form a continuous sheet."

According to Otey's findings, palladin belongs to a small group of cytoskeletal adhesion proteins that seem to provide molecular 'glue' for maintaining cellular shape and for the attachment of cells to one another via their plasma membranes. For example, fibroblasts are spindle-shaped cells involved in connective tissue, collagen formation and are also crucial to wound healing. In these cells, palladin is very concentrated near attachment points to the plasma membrane.

On the other hand, palladin is absent, not expressed, in some undifferentiated cells; that is, in cells which haven't achieved their genetically predetermined shape. Thus, the protein is absent in precursor stem cells. "So this indicates that palladin plays a role in forming the new cytoskeleton of cells that are beginning to differentiate and take on their specialized shape," she said.

According to Otey, an exciting thing about palladin is it's presence in different forms, different molecular weights. "In many different types of cells, one form of palladin may be necessary for tight adhesion and another for migration, or movement," she said. The Carolina scientist notes that a heavier form of palladin is more highly present, or expressed, in metastatic cancer cells - tumor cells that spread beyond their point of origin.

"It is also this form of palladin we see highly expressed in the early placenta, which of course is an 'invasive' organ," said Otey.

And it is during the first half of the ovulatory cycle that the womb prepares for embryo implantation by undergoing very dramatic changes in cell shape. A palladin form of greater molecular mass occurs during that time and then diminishes later in the cycle. "So again its expression correlates with these very dynamic structural changes," Otey noted. "That's why we think there's clearly a role for palladin from the point of view of the embryo and the point of view of the placenta."

Still, as the researcher points out, exactly what the new protein does in normal cells and in cancer cells remains to be clarified further. Her laboratory is seeking answers.

"In this first paper we describe the discovery of this protein. It's basically a birth announcement," Otey said. "All of the subsequent studies will be built on this. In the pipeline we have projects related to neuroscience, orthopedic research, developmental biology, including embryo implantation, and we're studying palladin in cancer metastasis. I think in the next couple of years we'll see results that are more specific to public health concerns."
-end-
This research is supported by grants from the National Institutes of Health.

Media note: contact Dr. Otey at 919-966-8239, e-mail: carol_otey@med.unc.edu
School of Medicine contact, Leslie H. Lang, 919-843-9687, e-mail: llang@med.unc.edu

University of North Carolina Health Care

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer 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.