F-box protein specificity for g1 cyclins is dictated by subcellular localization.

ABSTRACT: Levels of G1 cyclins fluctuate in response to environmental cues and couple mitotic signaling to cell cycle entry. The G1 cyclin Cln3 is a key regulator of cell size and cell cycle entry in budding yeast. Cln3 degradation is essential for proper cell cycle control; however, the mechanisms that control Cln3 degradation are largely unknown. Here we show that two SCF ubiquitin ligases, SCF(Cdc4) and SCF(Grr1), redundantly target Cln3 for degradation. While the F-box proteins (FBPs) Cdc4 and Grr1 were previously thought to target non-overlapping sets of substrates, we find that Cdc4 and Grr1 each bind to all 3 G1 cyclins in cell extracts, yet only Cln3 is redundantly targeted in vivo, due in part to its nuclear localization. The related cyclin Cln2 is cytoplasmic and exclusively targeted by Gr

SUBMITTER: Landry BD 

PROVIDER: S-EPMC3405998 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature