Missing link in cell division discovered
26 July 2010
Researchers from The George Washington University Medical
Center have identified a protein that plays a crucial role in cell
division and is over-expressed in breast cancer.
The discovery promises to revolutionize the understanding of key
aspects of cellular lifecycle and offers a new avenue for cancer
The protein, Arpc 1b, serves as both an activator as well as a
substrate for Aurora A, an enzyme that plays a central role in
cellular reproduction in normal cells but is overexpressed in
several cancers. This represents perhaps the earliest step in
mitosis and serves as the missing link regarding the role this
protein plays in starting the cell cycle and what keeps the process
in balance. The authors discovered that Arpc1b also exists as a
standalone protein and believe that it might also play an
independent role outside its established contribution to actin
More than just an observation of how cells divide, this discovery
also offers a potential target for pharmaceutical therapy. Both
Aurora A and Arpc1b are over-expressed in breast cancers.
Pharmaceutical inhibitors targeting Aurora A are currently available
and thus, could be combined with other future targeting strategies.
The researchers discovered that an over-expression of Arpc1b
promotes tumorigenic properties of breast cancer cells. Scientists
believe that if they can someday find a means of suppressing the
activity of Arpc 1b in cancer cell, the balance could be restored to
this dynamic yet tightly regulated biological event.
The discovery, reported in the article "Arpc 1b, a centrosomal
protein, is both an activator and substrate of Aurora A," furthers
the science world's understanding of what happens during the
fundamental process of mitosis, when cells divide. The article was
published in the current issue of The Journal of Cell Biology.
"This represents a crucial moment when the division of genetic
material is still equally distributed. An even exchange is critical
for stable genetic changes," said Rakesh Kumar, Ph.D., chair of the
GW Department of Biochemistry and Molecular Biology. In mitosis,
cells begin to divide and genetic material coalesces around separate
poles to form new cells. If all goes well that material is evenly
distributed and two genetically identical "daughter cells" are
formed. If something goes awry, however, it can result in the
cascading production of aberrant cells with unequal and less ordered
DNA and possibly cancer.
"This discovery is the result of persistence and the commitment
to scientific breakthrough," said Dr. Kumar. "Asking a question and
staying involved until you find the answer to close the loop is
critical in scientific discovery." In this case the earliest piece
of data used here was obtained in 2001.
To learn more about this research, view The Journal of Cell