I have a HA-tagged protein that when expressed, show up as a 40kD protein… and there is a faint band about ~43-45kD… this faint band becomes a major band with MG132 addition to transfected cells.
So, it looks like ubiquitination…
But I cannot detect the ubiquitin (the upper band) using anti-Ubi antibody from Santa Cruz. Also tried anti-SUMO from Santa Cruz and it is not positive as well.
any ideas, advice, or experience to share?