Cyclin E Both Regulates and Is Regulated by Calpain 2, a Protease Associated with Metastatic Breast Cancer Phenotype

Libertini, Stephen J.; Robinson, Brian; Dhillon, Navdeep; Glick, D.R.; George, Michael; Dandekar, Satya; Gregg, Jeffrey P.; Sawai, Earl T.; Mudryj, Maria

doi:10.1158/0008-5472.can-05-1666

Cited by 46 publications

(46 citation statements)

References 56 publications

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“…2A). We previously showed that proteolysis of the calpain substrate focal adhesion kinase (FAK) is a good indicator of calpain activity (22). Calpeptin treatment of R1 cells reduced the levels of LMW-FAK ( Fig.…”

Section: Resultsmentioning

confidence: 97%

ERK Regulates Calpain 2-induced Androgen Receptor Proteolysis in CWR22 Relapsed Prostate Tumor Cell Lines

Chen

Libertini

Wang

et al. 2010

Journal of Biological Chemistry

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and the ʈ Veterans Mather, California 95655 Androgen ablation therapy is effective in treating androgendependent prostate tumors; however, tumors that can proliferate in castrate levels of androgen eventually arise. We previously reported that in CWR22Rv1 (Rv1) cells, the protease calpain 2 can cleave the androgen receptor (AR) into a constitutively active ϳ80,000 low molecular weight (LMW) form. In this study, we further dissect the mechanisms that produce the AR LMW forms using Rv1 cells and the related CWR22-R1 (R1) cells. The 39-amino acid insertional mutation in the Rv1-AR (E3DM-AR) sensitizes this AR to calpain 2 proteolysis. R1 cells encode the same AR molecule as the parental CWR22 xenograft. Using calpain 2 small interfering RNA and calpeptin, we find that calpain 2 plays a role in the generation of the LMW-AR in R1 cells. Furthermore, LMW-AR expression is regulated by the activation of calpain 2 by ERK 1 and 2. Inhibition of ERK phosphorylation or small interfering RNA-mediated decrease of ERK expression reduces LMW-AR levels in R1 cells. Conversely, activation of the MAPK pathway results in increased ERK phosphorylation and increased levels of LMW-AR. Finally, analyses of human tumor samples found that LMW-AR levels are higher in tumors that have an increased calpain/calpastatin ratio and/or increased levels of phospho-ERK (pERK). This suggests that a higher calpain/calpastatin ratio collaborates with activated ERK to promote the generation of the LMW-AR.

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Section: Resultsmentioning

confidence: 97%

ERK Regulates Calpain 2-induced Androgen Receptor Proteolysis in CWR22 Relapsed Prostate Tumor Cell Lines

Chen

Libertini

Wang

et al. 2010

Journal of Biological Chemistry

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“…For example, in Src-transformed cells, FAK is extensively cleaved compared with other adhesion complex proteins (38,39). In addition, human tumors overexpressing cyclin E have been associated with increased proteolysis of FAK (40). By contrast, in myoblasts overexpressing calpastatin, the proteolytic patterns of talin and FAK are unchanged, whereas an accumulation of MARCKS (myristoylated alanine-rich C kinase substrate) has been observed, indicating that calpain may preferentially cleave MARCKS to affect myoblast migration (41,42).…”

Section: Discussionmentioning

confidence: 99%

Regulation of Adhesion Dynamics by Calpain-mediated Proteolysis of Focal Adhesion Kinase (FAK)

Chan

Bennin

Huttenlocher

2010

Journal of Biological Chemistry

181

165

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The coordinated and dynamic regulation of adhesions is required for cell migration. We demonstrated previously that limited proteolysis of talin1 by the calcium-dependent protease calpain 2 plays a critical role in adhesion disassembly in fibroblasts ( The coordinated and dynamic regulation of adhesions is central for cell migration in both normal and pathological processes (1). Cell migration is initiated by forming protrusions, which are stabilized by integrin-mediated adhesions that establish structural and signaling linkages between the extracellular matrix and the actin cytoskeleton. Subsequently, actomyosin contractility drives forward propulsion, and finally, adhesions are disassembled to allow for directional movement. Thus, it is not surprising that efficient cell migration necessitates precise spatial and temporal control of these events. However, the mechanisms governing the formation and disassembly of adhesions are still not well understood.A prominent component involved in this regulation is focal adhesion kinase (FAK).2 FAK promotes cell migration by its capacity to orchestrate signals between integrin and growth factor receptors (2). Downstream of integrin or growth factor stimulation, FAK is phosphorylated at Tyr-397, which is an important binding site for Src family kinases (3). Previous studies have demonstrated a critical role for FAK as a regulator of adhesion dynamics (4 -7). In addition, FAK has been shown to mediate the tyrosine phosphorylation of p190RhoGAP as a negative regulator of Rho activity in focal adhesion turnover and polarity (5, 8). Furthermore, microtubule-induced focal adhesion disassembly requires FAK and dynamin (9). Nevertheless, the mechanisms by which FAK regulates the disassembly of focal adhesions remain to be elucidated. Evidence has emerged supporting the role of the calpain family of intracellular calcium-dependent proteases in regulating cell migration (10 -14). Calpains have been proposed to regulate migration, at least in part, through their ability to modulate the dynamics of adhesions (15). Numerous calpain targets have been identified, some of which are proteins that are present in focal adhesions, including talin, paxillin, and FAK (16). Thus, it is likely that proteolysis of these substrates contributes to the regulation of adhesion dynamics and cell migration.The involvement of both FAK and calpain in regulating the turnover of adhesions prompted us to investigate the cleavage of FAK by calpain as a possible mechanism by which FAK affects adhesion dynamics. We demonstrated previously that calpain-mediated proteolysis of talin regulates adhesion dynamics (17). Here, we show that FAK also regulates talin dynamics. We have identified the calpain cleavage site of FAK and have generated a mutant form of FAK that is resistant to calpain proteolysis. Expression of wild-type but not calpainresistant FAK restores the adhesion dynamics of talin in FAKdeficient cells. Taken together, our findings suggest a novel role for calpain-mediated cleavage of FAK in regulating...

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“…Calpain is often hyperactivated in tumor cells (Carragher et al, 2004;Libertini et al, 2005), where it plays a major role in migration and metastasis due to its ability to cleave cytoskeletal proteins. Interestingly, PP2A negatively regulates calpain in nicotine-stimulated cell migration (Xu and Deng, 2006), in line with its tumor suppressor role.…”

Section: Discussionmentioning

confidence: 99%

Calpain small-1 modulates Akt/FoxO3A signaling and apoptosis through PP2A

et al. 2008

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Cyclin E Both Regulates and Is Regulated by Calpain 2, a Protease Associated with Metastatic Breast Cancer Phenotype

Cited by 46 publications

References 56 publications

ERK Regulates Calpain 2-induced Androgen Receptor Proteolysis in CWR22 Relapsed Prostate Tumor Cell Lines

ERK Regulates Calpain 2-induced Androgen Receptor Proteolysis in CWR22 Relapsed Prostate Tumor Cell Lines

Regulation of Adhesion Dynamics by Calpain-mediated Proteolysis of Focal Adhesion Kinase (FAK)

Calpain small-1 modulates Akt/FoxO3A signaling and apoptosis through PP2A

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