title: Protein kinase Cη is targeted to lipid droplets.
abstract: Protein kinase C (PKC) is a family of kinases that regulate numerous cellular functions. They are classified into three subfamilies, i.e., conventional PKCs, novel PKCs, and atypical PKCs, that have different domain structures. Generally, PKCs exist as a soluble protein in the cytosol in resting cells and they are recruited to target membranes upon stimulation. In the present study, we found that PKCη tagged with EGFP distributed in lipid droplets (LD) and induced a significant reduction in LD size. Two other novel PKCs, PKCδ and PKCε, also showed some concentration around LDs, but it was less distinct and less frequent than that of PKCη. Conventional and atypical PKCs (α, βII, γ, and ζ) did not show any preferential distribution around LDs. 1,2-Diacylglycerol, which can activate novel PKCs without an increase of Ca(2+) concentration, is the immediate precursor of triacylglycerol and exists in LDs. The present results suggest that PKCη modifies lipid metabolism by phosphorylating unidentified targets in LDs.
authors: Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, 466-8550, Japan.
authors: Michitaka
authors: M
authors: Suzuki
authors: Yuri
authors: Y
authors: Iio
authors: Naoaki
authors: N
authors: Saito
authors: Toyoshi
authors: T
authors: Fujimoto
mesh_terms: D002118:Calcium / Q000737:chemistry; D002460:Cell Line; D004075:Diglycerides / Q000737:chemistry; D049452:Green Fluorescent Proteins; D006801:Humans; D050356:Lipid Metabolism; D008055:Lipids; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D014280:Triglycerides / Q000737:chemistry
chemical_list: C011439:1,2-diacylglycerol; D004075:Diglycerides; D008055:Lipids; D014280:Triglycerides; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C081975:protein kinase C eta; D011493:Protein Kinase C; D002118:Calcium