TY - JOUR
T1 - JNK and ceramide kinase govern the biogenesis of lipid droplets through activation of group IVA phospholipase A2
AU - Gubern, Albert
AU - Barceló-Torns, Miguel
AU - Barneda, David
AU - López, José M.
AU - Masgrau, Roser
AU - Picatoste, Fernando
AU - Chalfant, Charles E.
AU - Balsinde, Jesús
AU - Balboa, María A.
AU - Claro, Enrique
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2009/11/20
Y1 - 2009/11/20
N2 - The biogenesis of lipid droplets (LD) induced by serum depends on group IVA phospholipase A2 (cPLA2α). This work dissects the pathway leading to cPLA2α activation and LD biogenesis. Both processes were Ca2+-independent, as they took place after pharmacological blockade of Ca2+ transients elicited by serum or chelation with 1,2-bis(2-aminophenoxy)ethaneN′,N,N′,N′-tetraacetic acid tetrakis(acetoxymethyl ester). The single mutation D43N in cPLA2α, which abrogates its Ca2+ binding capacity and translocation to membranes, did not affect enzyme activation and formation of LD. In contrast, the mutation S505A did not affect membrane relocation of the enzyme in response to Ca2+ but prevented its phosphorylation, activation, and the appearance of LD. Expression of specific activators of different mitogen-activated protein kinases showed that phosphorylation of cPLA2α at Ser-505 is due to JNK. This was confirmed by pharmacological inhibition and expression of a dominant-negative form of the upstream activator MEKK1. LD biogenesis was accompanied by increased synthesis of ceramide 1-phosphate. Overexpression of its synthesizing enzyme ceramide kinase increased phosphorylation of at Ser-505 and formation of LD, and its down-regulation blocked the phosphorylation of cPLA2α and LD biogenesis. These results demonstrate that LD biogenesis induced by serum is regulated by JNK and ceramide kinase.
AB - The biogenesis of lipid droplets (LD) induced by serum depends on group IVA phospholipase A2 (cPLA2α). This work dissects the pathway leading to cPLA2α activation and LD biogenesis. Both processes were Ca2+-independent, as they took place after pharmacological blockade of Ca2+ transients elicited by serum or chelation with 1,2-bis(2-aminophenoxy)ethaneN′,N,N′,N′-tetraacetic acid tetrakis(acetoxymethyl ester). The single mutation D43N in cPLA2α, which abrogates its Ca2+ binding capacity and translocation to membranes, did not affect enzyme activation and formation of LD. In contrast, the mutation S505A did not affect membrane relocation of the enzyme in response to Ca2+ but prevented its phosphorylation, activation, and the appearance of LD. Expression of specific activators of different mitogen-activated protein kinases showed that phosphorylation of cPLA2α at Ser-505 is due to JNK. This was confirmed by pharmacological inhibition and expression of a dominant-negative form of the upstream activator MEKK1. LD biogenesis was accompanied by increased synthesis of ceramide 1-phosphate. Overexpression of its synthesizing enzyme ceramide kinase increased phosphorylation of at Ser-505 and formation of LD, and its down-regulation blocked the phosphorylation of cPLA2α and LD biogenesis. These results demonstrate that LD biogenesis induced by serum is regulated by JNK and ceramide kinase.
UR - http://www.scopus.com/inward/record.url?scp=70450235103&partnerID=8YFLogxK
UR - https://www.jbc.org/article/S0021-9258(20)37828-5/fulltext
U2 - 10.1074/jbc.M109.061515
DO - 10.1074/jbc.M109.061515
M3 - Article
C2 - 19778898
SN - 0021-9258
VL - 284
SP - 32359
EP - 32369
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 47
ER -