Duplicate gene and its parental copy can subfunctionalize so that each carries out only some of the roles that the ancestral gene performed. 

Ex- a duplicate of the β-hemoglobin locus is expressed in the fetus. 

TLS Online TPP Program

#Id: 8156

#Section 3: Genetics, Cellular and Molecular Biology

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: 8154

#Section 3: Genetics, Cellular and Molecular Biology

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: 8153

#Section 3: Genetics, Cellular and Molecular Biology

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: 8152

#Section 3: Genetics, Cellular and Molecular Biology

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

TLS Online TPP Program

#Id: 8151

#Section 3: Genetics, Cellular and Molecular Biology

Sec12

acts as a GEF factor for Sar1

TLS Online TPP Program

#Id: 8150

#Section 3: Genetics, Cellular and Molecular Biology

Sar1 is the only GTPase switch protein activated at the ER membrane