Proteomic analysis reveals a role for protein kinase C-alpha in phagosome maturation.
Acquisition of microbicidal properties by phagosomes requires the action of molecules which regulate the interactions between phagosomes and endocytic organelles. Members of the protein kinase C (PKC) superfamily of serine/threonine kinases are recruited to phagosomes with various kinetics during phagolysosome biogenesis. To study the role of PKC-alpha in this process, we compared the composition of latex bead-containing phagosomes isolated from control and dominant-negative (DN) PKC-alpha-overexpressing RAW 264.7 macrophages. Western blot analysis indicated that the levels of both lysosomal-associated membrane protein-1 and flotillin-1, which are acquired through interactions with late endosomes and lysosomes, are reduced in phagosomes from DN PKC-alpha-overexpressing macrophages. Proteomic characterization of latex bead-containing phagosomes revealed that recruitment of the small GTPase Rab7, cathepsin D, and cathepsin S is inhibited by DN PKC-alpha. Collectively, these data provide evidence that PKC-alpha plays a role in phagolysosome biogenesis, a critical process of the innate immune response against infections.
Ng Yan Hing
John Derek
JD
INRS-Institut Armand-Frappier, Université du Québec, Laval, Que., Canada H7V 1B7.
Desjardins
Michel
M
Descoteaux
Albert
A
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015415:Biomarkers; D002402:Cathepsin D / Q000235:genetics / Q000378:metabolism; D002403:Cathepsins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008863:Microspheres; D009154:Mutation; D010588:Phagosomes / Q000502:physiology*; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D020543:Proteome / Q000032:analysis*; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D000090802:rab7 GTP-Binding Proteins
D015703:Antigens, CD; D015415:Biomarkers; D051907:Lysosomal Membrane Proteins; D008565:Membrane Proteins; D020543:Proteome; C106354:flotillins; D000090802:rab7 GTP-Binding Proteins; C000716465:rab7 GTP-binding proteins, mouse; C496630:Prkca protein, mouse; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D002403:Cathepsins; C028217:cathepsin S; D002402:Cathepsin D; D020691:rab GTP-Binding Proteins