Hi all

I know there are some mAb for jak and stat proteins that react with their phosphorylated form. I want to know after addition of il-2 to a blood sample, can I measure jak3/stat5 ativation level with mAb.


Thanks in advance

Yes, you can!
Check out:
Sexl et al., 2003
Blood. 2003 Jun 15;101(12):4937-43. Epub 2003 Feb 6.
Method section

fery said:

Hi all I know there are some mAb for jak and stat proteins that react with their phosphorylated form. I want to know after addition of il-2 to a blood sample, can I measure jak3/stat5 ativation level with mAb. Thanks in advance

Hi, I assume you're working in T-cells? Cell Signaling Technology has both rabbit polyclonal and mouse monoclonals against both total and phospho-Stat5 (Tyr694); they don't appear to have anything for Jak3, just Jaks 1 & 2 and Tyk2. Both Santa Cruz and Sigma have Abs to Jak3, but I don't believe any of these are specific for the phosphorylated form. You might want to contact some of these guys and ask a technical rep if they have any that aren't yet in the catalogs, or try to find someone e.g. like the authors listed in the Blood paper listed by "vanishing" who can provide you with the appropriate reagents. Good luck.

This paper might be of some help


1: Am J Transplant. 2002 Jan;2(1):31-40. Related Articles, Links


Effect of anti-IL-2Ralpha antibody on IL-2-induced Jak/STAT signaling.

Tkaczuk J, Yu CL, Baksh S, Milford EL, Carpenter CB, Burakoff SJ, McKay DB.

Abs to both serine and tyrosine phosphorylated forms of Jak-3 are available from SC, and probably other companies too. The SC Abs, however, give us 2-3 bands, with one prominent band. The tyrosine phos Ab is weaker than the serine phos one- which is weird, because tyrosine phos is responsible for maximal Stat3 activation, esp in conjunction with serine phosphorylation, whereas serine phosphorylation by itself is weaker.