Calpain2 mediates Rab5-driven focal adhesion disassembly and cell migration

Abstract

The early endosome protein Rab5 was recently shown to promote cell migration by enhancing focal adhesion disassembly through mechanisms that remain elusive. Focal adhesion disassembly is associated to proteolysis of talin, in a process that requires calpain2. Since calpain2 has been found at vesicles and endosomal compartments, we hypothesized that Rab5 stimulates calpain2 activity, leading to enhanced focal adhesion disassembly in migrating cells. We observed that calpain2 co-localizes with EEA1-positive early endosomes and co-immunoprecipitates with EEA1 and Rab5 in A549 lung carcinoma cells undergoing spreading, whereas Rab5 knock-down decreased the accumulation of calpain2 at early endosomal-enriched fractions. In addition, Rab5 silencing decreased calpain2 activity, as shown by cleavage of the fluorogenic substrate tBOC-LM-CMAC and the endogenous substrate talin. Accordingly, Rab5 promoted focal adhesion disassembly in a calpain2-dependent manner, as expression of GFP-Rab5 accelerated focal adhesion disassembly in nocodazole-synchronized cells, whereas pharmacological inhibition of calpain2 with N-acetyl-Leu-Leu-Met prevented both focal adhesion disassembly and cell migration induced by Rab5. In summary, these data uncover Rab5 as a novel regulator of calpain2 activity and focal adhesion proteolysis leading to cell migration.

Metastasising Fibroblasts Show an HDAC6-Dependent Increase in Migration Speed and Loss of Directionality Linked to Major Changes in the Vimentin Interactome

“…In addition to talin 1, tubacin reduced the levels of the small Rho GTPase Rab5C in the vimentin interactome, as well as Rab GDP dissociation inhibitor β (GDI2), a GDI that inhibits Rab5C. Rab5C is required for focal adhesion formation, as it activates the calcium-dependent protease calpain 2 and increases the turnover of focal adhesion proteins, including talin 1, to promote cell migration [32,35]. It is therefore possible that GDI-inactivated Rab5C is released from vimentin upon tubacin treatment, to result in increased outside-in signalling over focal adhesions.…”

Histatins, wound healing, and cell migration

“…Finally, cell migration requires coordinated detachment of the rear‐end and the disassembly of FAs, by mechanisms that remain poorly understood, although it is known to depend on FAK (Hamadi et al., ), calpain‐dependent proteolysis (Franco et al., ), and components of the endocytic machinery, such as dynamin, Dab2, clathrin, and Rab5 (Chao & Kunz, ; Ezratty, Bertaux, Marcantonio, & Gundersen, ; Ezratty, Partridge, & Gundersen, ; Mendoza et al., ). Particularly, recent studies from our laboratory showed that calpain2 is trafficked via early endosomes in a Rab5‐dependent manner, leading to FA disassembly (Mendoza et al., ).…”

Endosomal phosphatidylinositol 3‐phosphate controls synaptic vesicle cycling and neurotransmission

“…A third possibility is that PI(3)P directly or indirectly affects the localization of Calpain 2 itself. Such a scenario is supported by data from non-neuronal cells suggesting that Calpain 2 activation is mediated by Rab5-mediated recruitment to early endosomes (Mendoza et al, 2018), that is, organelles that contain PI(3)P. These scenarios will need to be studied in detail in the future. Second, given the multiple roles of Cdk5 in presynaptic neurotransmission and SV cycling, it is possible that hyperactivation of Cdk5 impinges not only on SV endocytosis (Tan et al, 2003;Armbruster et al, 2013) but may involve additional target proteins such as voltage-gated calcium channels (Kim & Ryan, 2010), crucial factors for the regulation of presynaptic release probability.…”