Detecting phosphorylation when sample material is scarce

Phosphorylation studies often combine weak signals with limited sample material. This application note tests phospho-STAT3 and phospho-ERK1/2 in PBMC lysates, followed by mild stripping and total-protein reprobing.

Scarce samples leave little room for an unclear result.

This application note investigates phosphoprotein detection in peripheral blood mononuclear cell lysates from rheumatoid arthritis patients, where sample material and target abundance can both be limiting.

VerdiBlot and two PVDF membranes were evaluated using wet transfer and chemiluminescent detection of:

• phospho-STAT3 and total STAT3
• phospho-ERK1/2 and total ERK1/2
• unstimulated and IL-6-stimulated PBMC samples
• protein loads from 1 to 50 µg
• mild stripping followed by reprobing on the same membrane

The sequential design allowed phosphorylated proteins to be detected first, followed by their corresponding total proteins after antibody removal. This helps reduce variability when comparing modified and unmodified protein states.

Under the tested conditions, VerdiBlot detected stimulation-dependent phosphorylation changes with low background, including phospho-STAT3 at a 1 µg protein load. After mild stripping, the membrane retained clear protein patterns for total-protein reprobing.

If your work involves cell signaling, phosphoproteins or limited clinical samples, the note provides the complete protocol, original blots and side-by-side results.

Read the complete application note:
https://www.verdiblot.com/_files/ugd/de6bd3_e3af66e86627423b84ce88ffb502639d.pdf