Internal control of the coated vesicle pp50-specific kinase complex

Area of Science:

• Cell Biology
• Molecular Biology
• Protein Biochemistry

Background:

• Coated vesicles feature a lattice of triskelion protein complexes.
• Triskelions are composed of clathrin heavy and light chains.
• Coated vesicles contain specific proteins, including a 50K protein (pp50).

Purpose of the Study:

• To investigate the nature of the protein kinase activity within coated vesicles.
• To determine the relationship between the kinase, pp50, and clathrin components.
• To elucidate the regulatory mechanisms of pp50 phosphorylation.

Main Methods:

• Characterization of protein kinase activity in coated vesicles.
• Analysis of protein-protein interactions within the vesicle.
• Investigation of the role of clathrin light chains in phosphorylation.

Main Results:

• A stable multimolecular system comprising the coated vesicle kinase and pp50 was identified.
• Clathrin light chains, but not heavy chains, significantly stimulate pp50 phosphorylation.
• Vesicle integrity does not appear to influence pp50 phosphorylation.

Conclusions:

• Coated vesicle kinase and pp50 form a stable functional unit.
• Clathrin light chains play a regulatory role in pp50 phosphorylation.
• The pp50 phosphorylation system is an intrinsic component of coated vesicles.