HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 283, Issue 28, 99933, July 11, 2008

This Article Full Text (PDF) Author Profile Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Related Collections Papers Of The Week Social Bookmarking                      What's this?

A Double Dose of Structure Maintenance of Chromosome Phosphorylation

In response to ionizing radiation, cells activate an intra-S phase checkpoint to halt DNA synthesis and prevent replication of damaged DNA. One major component that activates this checkpoint is the protein structure maintenance of chromosome 1 (SMC1), which becomes phosphorylated following radiation damage. As SMC1 associates with several other proteins to form the cohesion complex, which is indispensable for proper chromosomal metabolism, Hao Luo and colleagues tested if any other members of this complex are involved in the intra-S phase checkpoint in this Paper of the Week. Using mass spectrometry analysis they discovered that the SMC3 protein was also phosphorylated at two different serines. However, although Ser-1083 phosphorylation was radiation-induced like SMC1, the Ser-1067 site, phosphorylated by the CK2 kinase, was constitutive. In addition, a S1067A mutant weakened the phosphorylation of Ser-1083, suggesting that this constitutive site "primes" SMC3 for the second phosphorylation. This interesting discovery provides the first example of a regulatory site for ionizing radiation (IR) damage that's not induced by radiation and suggests that non-induced protein phosphorylations may play important roles in DNA damage checkpoints.

One of the two phosphorylation sites on the cohesion complex protein SMC3 as identified by MS/MS analysis.

FOOTNOTES

See referenced article, J. Biol. Chem. 2008, 283, 19176-19183

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This Article Full Text (PDF) Author Profile Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Related Collections Papers Of The Week Social Bookmarking                      What's this?