THE CART RECEPTOR

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 CART肽是参与许多不同生理反应的肽神经递质和激素。虽然对肽的结构、加工和基因调控知之甚多，但对其突触后作用和受体知之甚少。 使用125 I-CART 61-102作为配体和未标记的CART 61-102或CART 55-102作为置换剂，在PC 12细胞中检测到高亲和力特异性结合。分化的PC 12细胞增加了几倍的特异性结合。 分化后发现特异性结合的增加被放线菌素D和放线菌酮抑制，表明特异性结合的增加依赖于RNA和蛋白质的合成。 CART 1-27是一种从未被证明能引发反应的肽，它没有取代125 I-CART 61 -102结合，也没有取代20多种其他被检测的肽。 然而，令人惊讶的是，发现PACAP 1-38和PACAP 6-38是CART结合的低亲和力抑制剂。 CART处理增加了35 S [gamma]GTP-S与PC 12细胞膜的结合。此外，完整PC 12细胞的CART处理以随着分化而增加、被百日咳毒素阻断并被PACAP 6-38拮抗的方式引起磷酸化ERK的稳健增加。 这些发现表明，在PC 12细胞中的CART结合位点反映了与Gi/o连接的G蛋白偶联受体，并且还证明PACAP 6-38可用作CART受体拮抗剂。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. CART peptides are peptide neurotransmitters and hormones that are involved in many different physiological responses. While much is known about the peptides regarding their structure, processing and gene regulation, less is known about their postsynaptic actions and receptors. Using 125I-CART 61-102 as a ligand and unlabeled CART 61-102 or CART 55-102 as displacers, high-affinity specific binding was detected in PC12 cells. Differentiation of the PC12 cells increased specific binding several-fold. The increase in specific binding found after differentiation was inhibited by actinomycin D and cycloheximide, suggesting that the increase in specific binding was dependent on RNA and protein synthesis. CART 1-27, a peptide that has never been shown to elicit responses, did not displace 125I-CART61-102 binding, nor did more than 20 other peptides that were examined. Surprisingly, however, PACAP 1-38 and PACAP 6-38 were found to be low-affinity inhibitors of CART binding. CART treatment increased binding of 35S [gamma]GTP-S to PC12 cell membranes. Moreover, CART treatment of intact PC12 cells elicited robust increases in phospho-ERK in a manner that was increased with differentiation, blocked by pertussis toxin and antagonized by PACAP 6-38. These findings suggest that the CART binding site in PC12 cells reflects a G protein-coupled receptor linked with Gi/o, and also demonstrate that PACAP 6-38 may be useful as a CART receptor antagonist.