Cullin 1, also known as CUL1, is a human protein and
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
from
cullin
Cullins are a family of hydrophobic scaffold proteins which provide support for ubiquitin ligases (E3). All eukaryotes appear to have cullins. They combine with RING proteins to form ''Cullin-RING ubiquitin ligases'' (CRLs) that are highly div ...
family.
This protein plays an important role in
protein degradation and protein
ubiquitination
Ubiquitin is a small (8.6 kDa) regulatory protein found in most tissues of eukaryotic organisms, i.e., it is found ''ubiquitously''. It was discovered in 1975 by Gideon Goldstein and further characterized throughout the late 1970s and 19 ...
.
This is an essential component of the
SCF (
SKP1-CUL1-
F-box protein) E3
ubiquitin ligase
A ubiquitin ligase (also called an E3 ubiquitin ligase) is a protein that recruits an E2 ubiquitin-conjugating enzyme that has been loaded with ubiquitin, recognizes a protein substrate, and assists or directly catalyzes the transfer of ubiquitin ...
complex, which mediates the
ubiquitination
Ubiquitin is a small (8.6 kDa) regulatory protein found in most tissues of eukaryotic organisms, i.e., it is found ''ubiquitously''. It was discovered in 1975 by Gideon Goldstein and further characterized throughout the late 1970s and 19 ...
of proteins involved in
cell cycle
The cell cycle, or cell-division cycle, is the sequential series of events that take place in a cell (biology), cell that causes it to divide into two daughter cells. These events include the growth of the cell, duplication of its DNA (DNA re ...
progression,
signal transduction
Signal transduction is the process by which a chemical or physical signal is transmitted through a cell as a biochemical cascade, series of molecular events. Proteins responsible for detecting stimuli are generally termed receptor (biology), rece ...
and
transcription. In the
SCF complex, it serves as a rigid scaffold that organizes the SKP1-F-box protein and
RBX1 subunits. May contribute to catalysis through positioning of the substrate and the
ubiquitin-conjugating enzyme
Ubiquitin-conjugating enzymes, also known as E2 enzymes and more rarely as ''ubiquitin-carrier enzymes'', perform the second step in the ubiquitination reaction that targets a protein for degradation via the proteasome. The ubiquitination process ...
.
This protein is a part of a SCF complex consisting of CUL1,
RBX1,
SKP1 and
SKP2
S-phase kinase-associated protein 2 is an enzyme that in humans is encoded by the ''SKP2'' gene.
Structure and function
Skp2 contains 424 residues in total with the ~40 amino acid F-box domain lying closer to the N-terminal region at the 94-1 ...
. It also interacts with
RNF7. Part of a complex with
TIP120A/
CAND1 and
RBX1. The unneddylated form interacts with TIP120A/CAND1 and the interaction negatively regulates the association with SKP1 in the SCF complex. Interacts with
COPS2.
It is expressed in lung
fibroblasts
A fibroblast is a type of biological cell typically with a spindle shape that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal tissues, and plays a critical role in wound healing. Fibrobla ...
.
The protein is
neddylated, which enhances the ubiquitination activity of SCF. Deneddylated via its interaction with the
COP9 signalosome (CSN) complex.
Further reading
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External links
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