tokens: In contrast , the action of GLP-1 at the CRE was not blocked by cotransfection with M1-CREB , an isoform that lacks a consensus serine residue serving as substrate for PKA mediated phosphorylation .
folded_tokens: in contrast , the action of glp-1 at the cre be not block by cotransfection with m1-creb , a isoform that lack a consensus serine residue serve as substrate for pka mediate phosphorylation .