P190-B, a Rho-GTPase-activating protein, is differentially expressed in terminal end buds and breast cancer

Cell Growth Differ. 2000 Jul;11(7):343-54.


Microdissection and differential display PCR were used to identify genes preferentially expressed in the highly proliferative terminal end buds (TEBs) in the mammary gland of 45-day-old virgin rats. One clone exhibited 87% homology to the human p190-B gene encoding a novel Rho-Gap. Using in situ hybridization, p190-B was detected in both the TEBs and the terminal ducts, with the highest expression observed in the outer layer of TEBs. During normal mammary gland development, p190-B mRNA expression was highest in the virgin mammary gland and decreased during late pregnancy and lactation. Interestingly, increased levels of p190-B mRNA relative to the normal mammary gland were seen in a subset of murine mammary tumors that appeared to be less well differentiated and potentially more aggressive. Transient transfection of a p190-B expression construct into MCF-10A human mammary epithelial cells resulted in disruption of the actin cytoskeleton, which suggests a role for p190-B in regulating the signaling pathways that influence cell migration and invasion. These results suggest that p190-B may be required for virgin mammary gland development, and its aberrant expression may occur in breast cancer.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / metabolism
  • Animals
  • Biomarkers
  • Breast / metabolism*
  • Cell Line
  • Coloring Agents
  • Cytoskeleton / metabolism
  • DNA, Complementary
  • DNA-Binding Proteins
  • Epithelial Cells / metabolism
  • Female
  • GTPase-Activating Proteins
  • Gene Expression Profiling
  • Guanine Nucleotide Exchange Factors*
  • Humans
  • In Situ Hybridization
  • Mammary Glands, Animal / anatomy & histology
  • Mammary Glands, Animal / growth & development*
  • Mammary Glands, Animal / metabolism*
  • Mammary Neoplasms, Experimental / genetics
  • Mammary Neoplasms, Experimental / metabolism*
  • Mammary Neoplasms, Experimental / pathology
  • Mice
  • Microscopy, Fluorescence
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Pregnancy
  • RNA / metabolism
  • Rats
  • Rats, Inbred WF
  • Recombinant Proteins / metabolism
  • Repressor Proteins
  • Transfection


  • ARHGAP35 protein, human
  • ARHGAP5 protein, human
  • Actins
  • Arhgap35 protein, mouse
  • Arhgap35 protein, rat
  • Arhgap5 protein, mouse
  • Biomarkers
  • Coloring Agents
  • DNA, Complementary
  • DNA-Binding Proteins
  • GTPase-Activating Proteins
  • Guanine Nucleotide Exchange Factors
  • Nuclear Proteins
  • Phosphoproteins
  • Recombinant Proteins
  • Repressor Proteins
  • RNA