| Abstract [eng] |
70-kDa heat shock protein (Hsp70) is a cytosolic protein which acts as a molecular chaperone. Under pathological conditions Hsp70 translocates into the plasma membrane. Moreover, the protein is detected in the extracellular milieu. Hsp70 does not have a consensus signal for their translocation via the classical Endoplasmic Reticulum - Golgi compartment. It is possible that the protein is transported by an alternative mechanism and its first step could be an interaction with the plasma membrane. The aim of this work was to form tethered lipid membranes (tBLM) of various compositions, to investigate their morphology using fluorescence microscopy and to use them in the study of the interaction of Hsp70 with tBLM by the electrochemical impedance spectroscopy. Furthermore, calcein leakage assay was used to investigate Hsp70 interaction with unilamellar vesicles. Two compositions of tBLM were successfully formed. They were composed of DOPC/DOPE/Chol/DOPS (20:30:20:30) and DOPC/Chol (60:40). In these, tBLM lipids formed clusters which are different in size and position. Electrochemical impedance spectroscopy data has showed, that Hsp70 interaction with tBLM has increased the conductance of tBLM and showed an exponential dependence on conductance of tBLM depending on Hsp70 concentration. Calcein leakage assay experiments revealed that Hsp70 had high affinity for vesicles composed of saturated DPPC lipids and negatively charged phosphatidylserine (in ratio % 80:20). |
