Skip to main content
. 2009 Oct 14;284(48):33107–33114. doi: 10.1074/jbc.M109.064485

FIGURE 4.

FIGURE 4.

The C terminus of Claspin is sufficient to stimulate Chk1 phosphorylation by ATR and acts synergistically with damaged DNA. A, the C terminus of Claspin is sufficient for stimulation of ATR phosphorylation of Chk1. Kinase assays were carried out with ATR-ATRIP, HisChk1-kd, and TopBP1 as described in the legend for Fig. 1 except with 0, 1, 2, 4, 8, or 16 nm full-length (FL) Claspin or Claspin Δ851 fragment. The error bars indicate the average deviation from the mean. α-P-Chk1, phospho-Chk1. B, Claspin and DNA synergistically stimulate ATR Kinase. Kinase assays were carried out with ATR-ATRIP, HisChk1-kd, and TopBP1-C fragment as described in A except with 75 mm KCl and with or without 16 nm Claspin Δ851 and 2 ng of BPDE-damaged DNA.