Have you tested your primary and secondary antibodies and ECL solution by dot blot? Just drop I AB, I + II AB, II AB on your membranes and check how they work.

Or have you stained you memrane after blotting (for example, Ponseau S staining) to check good protein transfer?

Were other proteins stained on this membrane?

Dear Mohamed S. Selim ,

I think it might be a problem to get these membrane bound proteins into solution. I assume you are spinning down the cell debris after lysis? I do think that there is most on the CDH5 and Claudin going. Is there SDS within you lysis buffer? You might want to take a look in the literature searching for soluble (cytoplasmic/small vesicle) and insoluble connexin (membrane bound) lysis buffers.

Best wishes

Soenke