OPOMNIK: IJS KOLOKVIJ, sreda, 9. 1. 2019, ob 13. uri, prof. dr. Eva Žerovnik

[Natasa Gosevac]

Vabimo vas na 6. predavanje iz sklopa "Kolokviji na IJS" v letu 2018/19, ki
bo v sredo, 9. januarja 2019, ob 13. uri v Veliki predavalnici Instituta
>Jožef Stefan<  na Jamovi cesti 39 v Ljubljani. Napovednik predavanja
najdete tudi na naslovu http://www.ijs.si/ijsw/Koledar_prireditev, posnetke
preteklih predavanj pa na http://videolectures.net/kolokviji_ijs. 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

prof. dr. Eva Žerovnik

Institut Jožef Stefan, Ljubljana

 

Človeški stefin B kot modelni protein za študij zvijanja in agregacije
proteinov

Mehanizmi zvijanja in agregacije proteinov so skupni večini proteinov.
Proteini se razlikujejo glede na to, ali so zviti ali intrinzično odviti, a
vsi agregirajo preko delno odvitih intermediatov in mehanizem večinoma
poteka kot nukleacija in rast. Da bi se naučili več o teh mehanizmih, smo
preučevali proteinsko zvijanje in agregacijo do amiloidnih fibril dveh
homolognih proteinov stefina A in B ter njunih himernih variant. Zatem smo
razširili študije zvitja in agregacije nekaterih EPM1 mutant stefina B tudi
na sesalske celice. Nenazadnje smo del raziskav posvetili splošnemu
mehanizmu, kako oligomeri amiloidogenih proteinov preluknjajo membrane.
Doslej smo preverili modelne membrane in pokazali, da oligomeri in
protofibrili stefina B sprožijo prehajanje kalceina preko membrane, povečajo
površinsko napetost, se vežejo na lipidno površino in sprožijo stopničaste
tokove. Kapaciteta oligomerov za vezavo membrane korelira s povečanjem
reaktivnih kisikovih zvrsti (ROS) v celicah, kar nazadnje pripelje do
celične smrti. Predstavili bomo nove raziskave, ki podpirajo hipotezo o
amiloidnih porah, ki predpostavlja, da se oligomeri amiloidogenih proteinov
obnašajo podobno kot peptidi, ki tvorijo pore. Ti oligomeri se verjetno
vežejo na različne celične membrane in jih celo preluknjajo. S sodobnimi
visoko ločljivimi mikroskopskimi metodami slikanja bi bilo najbrž mogoče te
oligomere (velikost od 20 do 200 nm) tudi videti ter tako ugotoviti, kje
natanko se nahajajo in katere celične procese sprožijo.

Predavanje bo v angleščini.

Lepo vabljeni!

 

*****




We invite you to the 6th Institute colloquium in the academic year 2018/19.
The colloquium will be held on Wednesday, January 9, 2019 at 1 PM in the
main Institute lecture hall, Jamova 39, Ljubljana. To read the abstract
click  http://www.ijs.si/ijsw/Koledar_prireditev. 

Past colloquia are posted on  http://videolectures.net/kolokviji_ijs.

********************************************

prof. dr. Eva Žerovnik

Institut Jožef Stefan, Ljubljana

 

Human stefin B as a model protein to study protein folding and aggregation

 

Folding and aggregation mechanisms are in common to most proteins. Proteins
differ whether they are folded or intrinsically unfolded/disordered,
however, all aggregate over partially unfolded intermediates and the
mechanism in most cases conforms to nucleation and growth. In order to get
to know more of the mechanism, we studied folding and aggregation to amyloid
fibrils of two homologous proteins, stefins A and B and their chimeric
variants. Further, we performed cellular studies of certain EPM1 stefin B
mutants. Part of our studies was devoted to the possible common mechanism of
how amyloid proteins form pores within membranes. Thus far we checked model
membranes and it was shown that oligomers and protofibrils of stefin B
release calcein from lipid vesicles, increase pressure on the lipid surface,
and finally lead to step-wise currents. The capacity of the oligomers to
bind to cellular membranes correlates with an increase of reactive oxygen
species (ROS) and leads ultimately to cell death. We will present novel
studies supporting the "amyloid pore" hypothesis, which assumes that the
oligomers of amyloidogenic proteins behave similarly to pore forming
peptides. The oligomers likely bind various cellular membranes and even
perforate them. With modern high-resolution microscopic methods it should be
possible to image these oligomers (of the size between 20 and 200 nm) and in
such a way determine their detailed localization and down-stream processes.

 

Cordially invited!

 

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