Studies of tyrosine phosphorylation and Src family tyrosine kinases in the lens epithelium

Shigeo Tamiya, Nicholas A Delamere

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

PURPOSE. Tyrosine phosphorylation regulates many aspects of cell function; thus, cells that have different roles often display different patterns of tyrosine phosphorylation. Because there is interest in differential function of the anterior and equatorial regions of the lens epithelium, studies were conducted to compare tyrosine phosphorylation in the two zones. METHODS. Anterior and equatorial regions of the porcine lens epithelium were collected. Using Western blot analysis, tissue homogenates were probed for tyrosine kinase proteins, phospho-Src, phosphotyrosine, and proliferating cell nuclear antigen (PCNA). RESULTS. Phosphotyrosine immunoblots revealed a marked difference between the pattern of tyrosine phosphorylation in anterior and equatorial regions of the epithelium. Many more bands were detected in the equatorial region, and band density was greater. The abundance of total and active Src family kinases was higher at the equator than at the anterior epithelium. Src kinase activity, which was measured directly by quantifying phosphorylation of a synthetic target peptide using 32P-γ-ATP, was detectable only at the equator. In organ-cultured lenses, PP2, a specific inhibitor of the Src kinase family, reduced the density of the phosphotyrosine protein bands. The abundance of PCNA, a protein expressed in proliferating cells, also was reduced in PP2-treated lenses. CONCLUSIONS. The results suggest that the higher Src family kinase activity at the equator contributes to the higher degree of protein phosphorylation observed in this region. The ability of PP2 to suppress PCNA expression suggests a possible link between the activity of Src family kinases and cell proliferation.

Original languageEnglish (US)
Pages (from-to)2076-2081
Number of pages6
JournalInvestigative Ophthalmology and Visual Science
Volume46
Issue number6
DOIs
StatePublished - Jun 2005
Externally publishedYes

Fingerprint

src-Family Kinases
Lenses
Tyrosine
Epithelium
Phosphorylation
Phosphotyrosine
Proliferating Cell Nuclear Antigen
Proteins
Swine
Adenosine Triphosphate
Western Blotting
Cell Proliferation
Peptides

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Studies of tyrosine phosphorylation and Src family tyrosine kinases in the lens epithelium. / Tamiya, Shigeo; Delamere, Nicholas A.

In: Investigative Ophthalmology and Visual Science, Vol. 46, No. 6, 06.2005, p. 2076-2081.

Research output: Contribution to journalArticle

@article{cdce4aa097404f24aeafd2c4fccc78c3,
title = "Studies of tyrosine phosphorylation and Src family tyrosine kinases in the lens epithelium",
abstract = "PURPOSE. Tyrosine phosphorylation regulates many aspects of cell function; thus, cells that have different roles often display different patterns of tyrosine phosphorylation. Because there is interest in differential function of the anterior and equatorial regions of the lens epithelium, studies were conducted to compare tyrosine phosphorylation in the two zones. METHODS. Anterior and equatorial regions of the porcine lens epithelium were collected. Using Western blot analysis, tissue homogenates were probed for tyrosine kinase proteins, phospho-Src, phosphotyrosine, and proliferating cell nuclear antigen (PCNA). RESULTS. Phosphotyrosine immunoblots revealed a marked difference between the pattern of tyrosine phosphorylation in anterior and equatorial regions of the epithelium. Many more bands were detected in the equatorial region, and band density was greater. The abundance of total and active Src family kinases was higher at the equator than at the anterior epithelium. Src kinase activity, which was measured directly by quantifying phosphorylation of a synthetic target peptide using 32P-γ-ATP, was detectable only at the equator. In organ-cultured lenses, PP2, a specific inhibitor of the Src kinase family, reduced the density of the phosphotyrosine protein bands. The abundance of PCNA, a protein expressed in proliferating cells, also was reduced in PP2-treated lenses. CONCLUSIONS. The results suggest that the higher Src family kinase activity at the equator contributes to the higher degree of protein phosphorylation observed in this region. The ability of PP2 to suppress PCNA expression suggests a possible link between the activity of Src family kinases and cell proliferation.",
author = "Shigeo Tamiya and Delamere, {Nicholas A}",
year = "2005",
month = "6",
doi = "10.1167/iovs.04-1199",
language = "English (US)",
volume = "46",
pages = "2076--2081",
journal = "Investigative Ophthalmology and Visual Science",
issn = "0146-0404",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "6",

}

TY - JOUR

T1 - Studies of tyrosine phosphorylation and Src family tyrosine kinases in the lens epithelium

AU - Tamiya, Shigeo

AU - Delamere, Nicholas A

PY - 2005/6

Y1 - 2005/6

N2 - PURPOSE. Tyrosine phosphorylation regulates many aspects of cell function; thus, cells that have different roles often display different patterns of tyrosine phosphorylation. Because there is interest in differential function of the anterior and equatorial regions of the lens epithelium, studies were conducted to compare tyrosine phosphorylation in the two zones. METHODS. Anterior and equatorial regions of the porcine lens epithelium were collected. Using Western blot analysis, tissue homogenates were probed for tyrosine kinase proteins, phospho-Src, phosphotyrosine, and proliferating cell nuclear antigen (PCNA). RESULTS. Phosphotyrosine immunoblots revealed a marked difference between the pattern of tyrosine phosphorylation in anterior and equatorial regions of the epithelium. Many more bands were detected in the equatorial region, and band density was greater. The abundance of total and active Src family kinases was higher at the equator than at the anterior epithelium. Src kinase activity, which was measured directly by quantifying phosphorylation of a synthetic target peptide using 32P-γ-ATP, was detectable only at the equator. In organ-cultured lenses, PP2, a specific inhibitor of the Src kinase family, reduced the density of the phosphotyrosine protein bands. The abundance of PCNA, a protein expressed in proliferating cells, also was reduced in PP2-treated lenses. CONCLUSIONS. The results suggest that the higher Src family kinase activity at the equator contributes to the higher degree of protein phosphorylation observed in this region. The ability of PP2 to suppress PCNA expression suggests a possible link between the activity of Src family kinases and cell proliferation.

AB - PURPOSE. Tyrosine phosphorylation regulates many aspects of cell function; thus, cells that have different roles often display different patterns of tyrosine phosphorylation. Because there is interest in differential function of the anterior and equatorial regions of the lens epithelium, studies were conducted to compare tyrosine phosphorylation in the two zones. METHODS. Anterior and equatorial regions of the porcine lens epithelium were collected. Using Western blot analysis, tissue homogenates were probed for tyrosine kinase proteins, phospho-Src, phosphotyrosine, and proliferating cell nuclear antigen (PCNA). RESULTS. Phosphotyrosine immunoblots revealed a marked difference between the pattern of tyrosine phosphorylation in anterior and equatorial regions of the epithelium. Many more bands were detected in the equatorial region, and band density was greater. The abundance of total and active Src family kinases was higher at the equator than at the anterior epithelium. Src kinase activity, which was measured directly by quantifying phosphorylation of a synthetic target peptide using 32P-γ-ATP, was detectable only at the equator. In organ-cultured lenses, PP2, a specific inhibitor of the Src kinase family, reduced the density of the phosphotyrosine protein bands. The abundance of PCNA, a protein expressed in proliferating cells, also was reduced in PP2-treated lenses. CONCLUSIONS. The results suggest that the higher Src family kinase activity at the equator contributes to the higher degree of protein phosphorylation observed in this region. The ability of PP2 to suppress PCNA expression suggests a possible link between the activity of Src family kinases and cell proliferation.

UR - http://www.scopus.com/inward/record.url?scp=22144444956&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=22144444956&partnerID=8YFLogxK

U2 - 10.1167/iovs.04-1199

DO - 10.1167/iovs.04-1199

M3 - Article

C2 - 15914626

AN - SCOPUS:22144444956

VL - 46

SP - 2076

EP - 2081

JO - Investigative Ophthalmology and Visual Science

JF - Investigative Ophthalmology and Visual Science

SN - 0146-0404

IS - 6

ER -