Identification of Ser/Thr phosphorylation sites in the C2-domain of phospholipase C ?2 (PLC?2) using TRPM7-kinase.

ABSTRACT: PLC-isozymes are central elements of cellular signaling downstream of numerous receptors. PLC?2 is a pivotal component of B cell receptor (BCR) signaling. The regulation of PLC?2-dependent signaling functions by Tyr-phosphorylation is well characterized, however, the potential role of Ser/Thr phosphorylation events remains undefined. TRPM7 is the fusion of a Ser/Thr kinase with an ion channel, and an essential component of Mg(2+)-homeostasis regulation. Although the interaction between the C2 domain of several PLC-isozymes and TRPM7 is well established, previous studies have focused on the effect of PLC-activity on TRPM7. Here, we investigated whether Ser/Thr phosphorylation sites in the C2 domain of PLC?2 could be identified using TRPM7-kinase. We show that TRPM7-kinase phosphorylates PLC?2 in its C2-domain at position Ser1164 and in the linker region preceding the C2-domain at position Thr1045. Using a complementation approach in PLC?2(-/-) DT40 cells, we found that the PLC?2-S1164A mutant fully restores BCR mediated Ca(2+)-responses under standard growth conditions. However, under hypomagnesic conditions, PLC?2-S1164A fails to reach Ca(2+)-levels seen in cells expressing PLC?2 wildtype. These results suggest that Mg(2+)-sensitivity of the BCR signaling pathway may be regulated by Ser/Thr phosphorylation of PLC?2.

SUBMITTER: Deason-Towne F 

PROVIDER: S-EPMC4049354 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature