Sic1, a protein, is a stoichiometric inhibitor[1] of Cdk1-Clb (B-type cyclins) complexes in the budding yeast Saccharomyces cerevisiae. Because B-type cyclin-Cdk1 complexes are the drivers of S-phase initiation, Sic1 prevents premature S-phase entry.[2] Multisite phosphorylation of Sic1 is thought to time Sic1 ubiquitination and destruction, and by extension, the timing of S-phase entry.[3]
^Schwob E, Böhm T, Mendenhall MD, Nasmyth K (October 1994). "The B-type cyclin kinase inhibitor p40SIC1 controls the G1 to S transition in S. cerevisiae". Cell. 79 (2): 233–44. doi:10.1016/0092-8674(94)90193-7. PMID 7954792. S2CID 34939988.
^Morgan DO (1997). The Cell Cycle: Principles of Control. London: New Science Press. pp. 200–1. ISBN 978-0-87893-508-6.
^Tripodi F, Zinzalla V, Vanoni M, Alberghina L, Coccetti P (August 2007). "In CK2 inactivated cells the cyclin dependent kinase inhibitor Sic1 is involved in cell-cycle arrest before the onset of S phase". Biochemical and Biophysical Research Communications. 359 (4): 921–7. doi:10.1016/j.bbrc.2007.05.195. PMID 17574209.
drivers of S-phase initiation, Sic1 prevents premature S-phase entry. Multisite phosphorylation of Sic1 is thought to time Sic1 ubiquitination and destruction...
transcriptional activator of Sic1 proteins. While degradation of Sic1 to a certain low level triggered the onset of S phase, accumulation of Sic1 to a certain high...
degradation of Sic1 in the late G1 phase of the cell cycle. The WD domain of Cdc4 binds to the phosphorylated form of Sic1. Each bond to a Sic1-Phosphate is...
transcriptional activator of Sic1 proteins. While degradation of Sic1 to a certain low level triggered the onset of S phase, accumulation of Sic1 to a certain high...
(NLS). SCF-Fbw7 targets Sic1—when at least six out of nine possible sites are phosphorylated—and Swi5 for degradation. Since Sic1 normally prevents premature...
for a number of highly dynamic and partially unfolded proteins, such as Sic1/Cdc4, p15 PAF, MKK7, Beta-synuclein and P27 As it is translated, polypeptides...
the ubiquitinated substrate. (e.g., Cdc 4, which binds the target protein Sic1; Grr1, which binds Cln). A HECT domain, which is involved in the transfer...
fuzziness. The most pertinent example is the cyclin-dependent kinase inhibitor Sic1, which binds to the SCF subunit of Cdc4 in a phosphorylation dependent manner...
anaphase-promoting complex. Cdc14 also dephosphorylates Swi5 to enhance transcription of Sic1, an inhibitor of Cdk1. This "simple" mitotic exit model became complicated...
occur in the pathway in which Sic1, is degraded in order for Cdk1-Clb (B-type cyclins) to allow entry into mitosis. Sic1 must be phosphorylated multiple...
Clb5,6-CDK complexes are inhibited by Sic1, so S-phase initiation requires phosphorylation and degradation of Sic1 by Cln1,2-CDK to proceed fully. Although...
targets numerous substrates - notably the cyclin-dependent kinase inhibitor Sic1 - for ubiquitin-mediated protein degradation. CDC34 is required for ubiquitin-mediated...
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