Question

 

"SUMOylation and ubiquitination reciprocally regulate α-synuclein degradation and pathological aggregation"

 

Take a look at Figure 3A. What would be the problem with the experiment if the band for actin were increasing in each lane of the gel (from left to right)? Would you be able to make any conclusions about the effects of PIAS on alpha-synuclein in this case? Why or why not

Answer 1

Actins are used as loading controls while the cytoplasmic protein samples are loading. Controls are helping to confirm the protein loading is the same throughout the gel and to normalize the signals from experimental samples.

Reason for the usage of Actin as loading control: Normally the amount of actin in cells will be very high. Any disturbances to the natural cell growth and changes in cell growth conditions will influence the actin synthesis. So actin can be used to ensure that the working cell line and proteins are normal (means the resulting bands are showing the right results), if there is no variation in actin protein levels across the gel. If the amount of actin is varying in each lane of gel, it means the growth of the cells is somehow disturbed and the experimental protein sample may showing the wrong result. You cannot make any conclusions regarding the protein interactions in this case.