Type II restriction endonucleases are remarkably stable and induce cleavage either, in most cases, within or immediately outside their recognition sequences.

TLS Online TPP Program

#Id: 8153

#Unit 2. Cellular Organization

A second function of small GTPases in vesicle formation is in the pinching off of a completed vesicle from the parent membrane

TLS Online TPP Program

#Id: 8154

#Unit 2. Cellular Organization

Sar1 GTPase drives the pinching off of COPII vesicles

ARF GTPase drives the pinching off of COPIvesicles

Dynamin GTPase drives the pinching off of clathrin-coated vesicles

TLS Online TPP Program

#Id: 8156

#Unit 2. Cellular Organization

Two different kinds of sorting signals:

Membrane cargo proteins carry cytoplasmic sorting signals

Soluble cargo proteins carry luminal sorting signals

TLS Online TPP Program

#Id: 8157

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 8158

#Unit 2. Cellular Organization

Soluble ER-resident proteins contain C-terminal KDEL sorting signal that allows them to be retrieved. 

TLS Online TPP Program

#Id: 8159

#Unit 2. Cellular Organization

KDEL receptor, located mainly in the cis-Golgi network and in both COPII and COPI vesicles, binds proteins bearing the KDEL sorting signal and returns them to the ER