B cells migrate to the lymphoid follicles. They are directed there by chemokine interactions between CXCL13, which is secreted by follicular dendritic cells (FDCs).

TLS Online TPP Program

#Id: 8158

#Section 3: Genetics, Cellular and Molecular Biology

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

TLS Online TPP Program

#Id: 8157

#Section 3: Genetics, Cellular and Molecular Biology

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.