Plasma proteins have:  Specific functions

(antibodies & blood clotting proteins)

Nonspecific functions (carriers for various hormones, solutes, and drugs)

TLS Online TPP Program

#Id: 8151

#Unit 2. Cellular Organization

Sec12

acts as a GEF factor for Sar1

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#Id: 8152

#Unit 2. Cellular Organization

After the vesicle coat is complete, the Sec23 coat subunit promotes GTP hydrolysis causes disassembly of the coat.

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