Manipulating signal delivery – plasma-membrane ERK activation in aPKC-dependent migration

Abstract

SummaryMembers of the PKC superfamily have been implicated in various migratory models and in particular in spatially restricted processes. However, defining the precise local events that underlie the PKC-dependent processes is constrained by the unspecific nature of interventions. Here we address this problem in relation to atypical PKC (aPKC) action, which in conjunction with the exocyst complex controls the polarised delivery of promigratory signals. A drug-dependent recruitment approach was employed to manipulate the local recruitment of signals to the leading edge of migrating cells, under conditions where the aPKC-exocyst control is globally abrogated. We found that activation of ERK but not JNK at focal adhesions recovers the majority of the migratory loss attributed to ERK action, demonstrating a necessary role for active plasma membrane ERK in the downstream signalling of aPKC-dependent migration. The data further show that restored focal adhesion dynamics are a contributing mechanism through which localized ERK activity influences this aPKC-exocyst-dependent migration.

ERK2 but not ERK1 mediates HGF-induced motility in non small cell lung carcinoma cell lines

“…We speculate that the ERK2-specific regulation of HGFinduced motility is due in part to specific ERK2-mediated paxillin phosphorylation, which would in turn affect focal adhesion dynamics as demonstrated in a different motility model (Boeckeler et al, 2010). Indeed we find that HGFtreatment results in an increase of the disassembly rate of paxillin-containing focal adhesions (Fig.…”

Binding of Dynein Intermediate Chain 2 to Paxillin controls Focal adhesion dynamics and migration.

“…It appears that on delivery to the leading edge dynein IC2 is involved in controlling FA turnover, phenocopying aPKC knock down and hence linking aPKC action in delivering dynein IC2 (dynein-dynactin complex) with its control of FA turnover. Because the inhibition of aPKCs triggers an increase in the FA content of another marker, zyxin (Boeckeler et al, 2010), we analysed the effects of dynein IC2 depletion on zyxin and paxillin at FAs (Fig. 3D).…”

“…3D). Because the aPKCs are important for the destabilisation of FAs (Boeckeler et al, 2010), (Rosse et al, 2009), we analysed the effect of the depletion of dynein IC2 on the disassembly rate of paxillin at FAs during cell migration using total internal reflection fluorescence (TIRF) microscopy and taking into consideration the localisation of the FAs (peripheral FA versus internal FA; Fig. 3C; supplementary material Movies 2, 3).…”

“…Changes in fluorescence intensity were normalized to the maximal value and plotted in semilogarithmic plots as a function of time. The rates were determined from the slopes of these graphs [disassembly: ln (max/minutes)] (Boeckeler et al, 2010).…”

The exocyst complex in exocytosis and cell migration

“…Kibra scaffolds the association between aPKC and the exocyst. The aPKCs, Kibra and the exocyst are shown to be required for NRK cell migration, and it is further demonstrated that they are necessary for the localized activation of c-Jun N-terminal kinase (JNK) and extracellular-signal-regulated kinase (ERK) at the leading edge of migrating cells (Rosse et al 2009;Boeckeler et al 2010). The activation of ERK and JNK in turn mediates the phosphorylation of paxillin, a component of focal adhesion complex, which is involved in the regulation of dynamic focal adhesions.…”