Saucedo-García, Mariana , Cruz-García, Felipe , Plasencia, Javier , Gavilanes-Ruíz, Marina .
Plant MAPK activation by long chain bases.
MAPK cascades are highly conserved pathways by which extracellular stimuli are transduced into intracellular responses. MAPK cascades consist of a three kinase module: a MAPKKK, a MAPKK and MAPK. MAPKKK, the first element in the cascade, is activated by an upstream element, probably associated to the membrane. MAPKKK phosphorylates a MAPKK and this in turn a MAPK. SIPK (salicylic acid induced protein kinase) and WIPK (wound activated protein kinase), are two tobacco MAPKs, that together with their orthologs in other plant species have been implicated in plant defense signaling. In animals, sphingolipids or their precursors activate several types of kinases, including MAPKs, while in plants only two MAPKs activated by two phosphorylated long chain bases (LCB) and a cerebroside have been reported. In this work, we describe in planta activation of MAPKs from maize embryos and bean leaves by fumonisin B1, a toxin that inhibits sphinganine N-acyl transferase, promoting accumulation of the substrate sphinganine, a LCB. When exogenous sphinganine (100 nM) was added, the same oscillatory activation pattern was observed with maximal activities at 30 min, 3 and 6 h. Cold, wounding and salicylic acid activation as well suggest that these LCB-activated MAPKs are involved in defense response to pathogens.
Financed by CONACYT (40311-Q), DGAPA, UNAM (IN207806), UC-MEXUS, University of California (CN-03-118). MSG is recipient of a fellowship (185332) from CONACYT.
Log in to add this item to your schedule
1 - UNAM, Dpt. Bioquímica, Conj. E, Facultad de Química, Cd. Universitaria. Coyoacán, México, D. F., 04510, México
2 - UNAM, Dpt. Bioquímica
long chain bases
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM