The amino group at C-2 bears a fatty acid in amide linkage.

The fatty acid is usually saturated or monounsaturated, with 16, 18, 22, or 24 carbon atoms.

Ceramide is the parent compound for this group.

TLS Online TPP Program

#Id: 8621

#Unit 2. Cellular Organization

The Cip/Kip family members bind to cyclin-bound CDKs and block the activity of cyclin D-, E-, A-, and B-containing complexes.

TLS Online TPP Program

#Id: 8622

#Unit 2. Cellular Organization

Cyclins are degraded through the action of two different E3-ligases:

1. SCF (Skp1, Cullin, and F-box proteins) 

2. APC/C or cyclosome

TLS Online TPP Program

#Id: 8623

#Unit 2. Cellular Organization

SCF and APC/C are multisubunit ubiquitin-protein ligases that belong to the RING finger family of ubiquitin-protein ligases.

TLS Online TPP Program

#Id: 8624

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 8625

#Unit 2. Cellular Organization

Human SCF complexes contain: 

Three core components - Cul1 subunit, RBX1, Skp1 

and a substrate-targeting F-box protein

TLS Online TPP Program

#Id: 8626

#Unit 2. Cellular Organization

RBX1 is a RING finger–containing protein that binds the E2 ubiquitin-conjugating enzyme.