Cullin 1, also known as CUL1, is a human protein and gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 from cullin

Cullin

Cullins are a family of hydrophobic proteins providing a scaffold for ubiquitin ligases . All eukaryotes appear to have cullins. They combine with RING proteins to form Cullin-RING ubiquitin ligases that are highly diverse and play a role in a myriad of cellular processes.Human genome contains...

 family.
This protein plays an important role in protein degradation and protein ubiquitination.

This is an essential component of the SCF (SKP1

Skp1

Skp1 is a small protein of approximately 160 amino acids. As a core component of the SCF-type E3 ubiquitin ligases that mediate protein degradation by the 26S proteosome, Skp1 plays key roles in cell-cycle progression, transcriptional regulation, signal transduction, and many other cellular...

-CUL1-F-box protein

F-box protein

F-box proteins are proteins containing at least one F-box domain. The first identified F-box protein is one of three components of the SCF complex, which mediates ubiquitination of proteins targeted for degradation by the proteasome....

) E3 ubiquitin ligase

Ubiquitin ligase

A ubiquitin ligase is a protein that in combination with an E2 ubiquitin-conjugating enzyme causes the attachment of ubiquitin to a lysine on a target protein via an isopeptide bond; the E3 ubiquitin ligase targets specific protein substrates for degradation by the proteasome...

 complex, which mediates the ubiquitination of proteins involved in cell cycle

Cell cycle

The cell cycle, or cell-division cycle, is the series of events that takes place in a cell leading to its division and duplication . In cells without a nucleus , the cell cycle occurs via a process termed binary fission...

 progression, signal transduction

Signal transduction

Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor. In turn, this receptor alters intracellular molecules creating a response...

 and transcription

Transcription (genetics)

Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...

. In the SCF complex

SCF complex

Skp, Cullin, F-box containing complex is a multi-protein E3 ubiquitin ligase complex catalyzing the ubiquitination of proteins destined for proteasomal degradation...

, it serves as a rigid scaffold that organizes the SKP1-F-box protein and RBX1

RBX1

RING-box protein 1 is a protein that in humans is encoded by the RBX1 gene.-Interactions:RBX1 has been shown to interact with CUL4A, CAND1, CUL1, CUL2, P70-S6 Kinase 1, DCUN1D1, CUL5 and CUL7.-Further reading:...

 subunits. May contribute to catalysis through positioning of the substrate and the ubiquitin-conjugating enzyme

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 covalently attaches ubiquitin, a short protein of 76...

.

This protein is a part of a SCF complex consisting of CUL1, RBX1

RBX1

RING-box protein 1 is a protein that in humans is encoded by the RBX1 gene.-Interactions:RBX1 has been shown to interact with CUL4A, CAND1, CUL1, CUL2, P70-S6 Kinase 1, DCUN1D1, CUL5 and CUL7.-Further reading:...

, SKP1

Skp1

Skp1 is a small protein of approximately 160 amino acids. As a core component of the SCF-type E3 ubiquitin ligases that mediate protein degradation by the 26S proteosome, Skp1 plays key roles in cell-cycle progression, transcriptional regulation, signal transduction, and many other cellular...

 and SKP2

SKP2

S-phase kinase-associated protein 2 is an enzyme that in humans is encoded by the SKP2 gene.- Function :This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box domain...

. It also interacts with RNF7

RNF7

RING-box protein 2 is a protein that in humans is encoded by the RNF7 gene.- External links :...

. Part of a complex with TIP120A/CAND1

CAND1

Cullin-associated NEDD8-dissociated protein 1 is a protein that in humans is encoded by the CAND1 gene.-Interactions:CAND1 has been shown to interact with CUL4A, CUL4B, RBX1, CUL1, DCUN1D1, CUL3 and CUL2.-Further reading:...

 and RBX1

RBX1

RING-box protein 1 is a protein that in humans is encoded by the RBX1 gene.-Interactions:RBX1 has been shown to interact with CUL4A, CAND1, CUL1, CUL2, P70-S6 Kinase 1, DCUN1D1, CUL5 and CUL7.-Further reading:...

. The unneddylated form interacts with TIP120A/CAND1 and the interaction negatively regulates the association with SKP1 in the SCF complex. Interacts with COPS2

COPS2

COP9 signalosome complex subunit 2 is a protein that in humans is encoded by the COPS2 gene.-Interactions:COPS2 has been shown to interact with IRF8, NIF3L1, Thyroid hormone receptor alpha and DAX1.-Further reading:...

.

It is expressed in lung fibroblasts.

The protein is neddylated

Neddylation

Neddylation is the process by which the ubiquitin like protein Nedd8 is conjugated to its target proteins. This process is analogous to ubiquitination, although relies on its own E1 and E2 enzymes...

, which enhances the ubiquitination activity of SCF. Deneddylated via its interaction with the COP9 signalosome (CSN) complex.

Further reading