Figure 4.

ERdj3 interacts with BiP and HPD motif is indispensable for the interaction. (A) Recombinant BiP was incubated alone (▵) or with wild-type (▪, WT J-ERdj3) or mutant (□, Mu J-ERdj3) J domains in an ATPase assay mixture for the indicated times. ATP hydrolysis was determined by chromatographic separation and quantified by PhosphorImager. (B) The ATP turnover rate was deduced from data obtained in A. (C) COS-1 cells were cotransfected with the indicated cDNAs clones, metabolically labeled and incubated with DSP to crosslink proteins. Cell lysates were prepared and immunoprecipitated with the indicated antisera, and precipitated proteins were analyzed by SDS-PAGE.