Figure 5.

RING-HC proteins are also involved in ubiquitination. (A) A GST fusion of amino acids 1–788 of mouse BRCA1 was evaluated for ubiquitination. (B) GS-bound GST-BRCA1 was incubated with (+) or without (−) TPEN, followed by washing of GS before a ubiquitination reaction. (C) Flag-tagged Siah-1 (Siah-1) or a mutant in the third coordination site (Siah-1 C → S) was translated with [³⁵S]Met in wheat germ lysate. Material was resolved directly on SDS/PAGE (Input) or evaluated for ubiquitination with or without UbcH5B. (D) GST fusions of Siah-1, the C → S Siah-1 mutant, or RING-deleted (Siah-1ΔR; ref. 12) were evaluated for ubiquitination.