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Tyrosine protein kinase expression in long‐term quiescent WI‐38 cells following growth factor simulation
Author(s) -
Korcz Aleksandra,
Soprano Dianne Robert,
Soprano Kenneth J.
Publication year - 1995
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240590106
Subject(s) - microbiology and biotechnology , biology , receptor tyrosine kinase , stimulation , tyrosine kinase , growth factor , epidermal growth factor , cell growth , dna synthesis , clone (java method) , kinase , cell cycle , signal transduction , tyrosine phosphorylation , receptor , cell , endocrinology , biochemistry , dna
We have used the WI‐38 cell long‐term quiescent model system to study the regulation of cell cycle progression at the molecular level. By modulating the length of time that WI‐38 cells are density arrested, it is possible to proportionately alter the length of the prereplicative or G‐1 phase which the cell traverses after growth factor stimulation in preparation for entry into DNA synthesis. Stimulation of long‐and short‐term density arrested WI‐38 cells with different growth factors or higher concentrations of individual growth factors does not alter the time required by long‐term cells to enter S after stimulation. However, the time during the prereplicative period for which these growth factors are needed is different. Long‐term quiescent WI‐38 cells require EGF to traverse the G‐0/G‐1 border but do not need and apparently cannot respond to IGF‐1 during the first 10 h after EGF stimulation, the length of the prolongation of the prereplicative phase. This suggests that EGF stimulation of long‐term quiescent WI‐38 cells initiates a series of molecular events which make these cells “competent” to respond to the “progression” growth factor, IGF‐1. In light of the well‐established role of protein tyrosine kinases in signal transduction, we set out to identify, clone, and analyze the expression of receptor and non‐receptor tyrosine kinases which potentially could play a role during the prolongation of the prereplicative phase in making the long‐term quiescent WI‐38 cells competent to respond to IGF‐1. We obtained 49 clones representing 11 different receptor and non‐receptor type protein tyrosine kinases. Analysis of expression of these clones revealed a variety of different patterns of expression. However, the most striking pattern was exhibited by IGF‐1 receptor. Our results suggest that induction of IGF‐1 receptor mRNA by EGF may be an important event in the establishment of competence by EGF in long‐term density arrested WI‐38 cells. © 1995 Wiley‐Liss, Inc.