Please use this identifier to cite or link to this item: https://scholarbank.nus.edu.sg/handle/10635/111870
Title: Elevation of membrane tyrosine phosphatase activity in density-dependent growth-arrested fibroblasts
Authors: Pallen, C.J. 
Tong, P.H. 
Keywords: Cell proliferation
Contact inhibition
Tyrosine dephosphorylation
Issue Date: 1991
Citation: Pallen, C.J.,Tong, P.H. (1991). Elevation of membrane tyrosine phosphatase activity in density-dependent growth-arrested fibroblasts. Proceedings of the National Academy of Sciences of the United States of America 88 (16) : 6996-7000. ScholarBank@NUS Repository.
Abstract: Swiss 3T3 cells harvested at high density contain a membrane protein-tyrosine-phosphatase (EC 3.1.3.48) whose specific activity is on average 8-fold higher than that of cells harvested at low or medium densities. Investigation of the conditions affecting this elevation of specific activity suggests that it is associated with density-dependent growth arrest. Fibroblasts in the exponentially doubling phase have a relatively low level of membrane phosphatase specific activity, which rises only as the rate of cell proliferation decreases and is maximal when cell growth is contact inhibited. These observations have been extended to BALB/c 3T3 fibroblasts and normal human diploid fibroblasts. The increase in membrane tyrosine phosphatase activity is coupled to density arrest and not to cellular quiescence in general, as no increase in phosphatase specific activity is detected when non-contact-inhibited cells are induced to arrest their growth through serum deprivation. The observed alterations in specific activity are attributable to a tyrosine phosphatase of Mr 37,000 that was purified and characterized from solubilized membrane fractions of Swiss 3T3 cells. A regulatory mechanism controlling tyrosine phosphatase activity may play a role in cell proliferation and growth arrest caused by cell contact.
Source Title: Proceedings of the National Academy of Sciences of the United States of America
URI: http://scholarbank.nus.edu.sg/handle/10635/111870
ISSN: 00278424
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

Page view(s)

55
checked on Mar 28, 2020

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.