Peptide aptamers as new tools to modulate clathrin-mediated internalisation — inhibition of MT1-MMP internalisation
1 MRC Cancer Cell Unit, Hutchison/MRC Research Centre, Hills Road, University of Cambridge, Cambridge, CB2 0XZ, UK
2 University of Cambridge, Department of Oncology, Cambridge Research Centre, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
3 Leeds Institute of Molecular Medicine, St James' University Hospital, University of Leeds, Leeds LS7 9TF, UK
BMC Cell Biology 2010, 11:58 doi:10.1186/1471-2121-11-58Published: 23 July 2010
Peptide aptamers are combinatorial protein reagents that bind to targets with a high specificity and a strong affinity thus providing a molecular tool kit for modulating the function of their targets in vivo.
Here we report the isolation of a peptide aptamer named swiggle that interacts with the very short (21 amino acid long) intracellular domain of membrane type 1-metalloproteinase (MT1-MMP), a key cell surface protease involved in numerous and crucial physiological and pathological cellular events. Expression of swiggle in mammalian cells was found to increase the cell surface expression of MT1-MMP by impairing its internalisation. Swiggle interacts with the LLY573 internalisation motif of MT1-MMP intracellular domain, thus disrupting the interaction with the μ2 subunit of the AP-2 internalisation complex required for endocytosis of the protease. Interestingly, swiggle-mediated inhibition of MT1-MMP clathrin-mediated internalisation was also found to promote MT1-MMP-mediated cell migration.
Taken together, our results provide further evidence that peptide aptamers can be used to dissect molecular events mediated by individual protein domains, in contrast to the pleiotropic effects of RNA interference techniques.