Redman R S, Berry R W
Northwestern University, Department of Cell, Molecular and Structural Biology, Chicago, IL 60611.
Brain Res Mol Brain Res. 1992 Oct;15(3-4):216-20. doi: 10.1016/0169-328x(92)90111-n.
ProELH is the prohormone to the bag cell egg-laying peptide of Aplysia. In addition to containing the structure of the hormone (ELH) itself, proELH also contains several other secreted peptides: AP (acidic peptide) and alpha-, beta-, and gamma-bag cell peptides (BCPs). The BCPs, ranging in length from 5 to 9 amino acids, are structurally similar in that they all contain the sequence Arg-Leu-Arg-Phe. An additional peptide from the atrial gland, Atrial A, also contains this sequence. The BCPs previously have been reported to have direct feedback (autocrine) effects on the bag cells, including electrophysiological excitation and inhibition. Moreover, some of these effects are temperature-dependent. The autocrine functions of these peptides were explored here by investigating their effects on bag cell cAMP levels. In addition, we monitored the effects of Atrial A, as well as ELH and AP, which are proELH products that do not have sequence homology with the BCPs. While ELH and AP have no effect on bag cell cAMP levels, the other peptides fall into two functional classes. alpha- and gamma-BCP produce an elevation of cAMP levels at 20 degrees and a depression at 15 degrees C. The elevation in cAMP is sensitive to low Ca2+/high Mg2+. beta-BCP and Atrial A elevate cAMP levels independently of temperature, and are insensitive to low Ca2+/high Mg2+. Our results suggest that there may be multiple bag cell receptors for these peptides with the Arg-Leu-Arg-Phe sequence representing a receptor-recognition motif.
前ELH是海兔袋状细胞产卵肽的前体激素。除了包含激素（ELH）本身的结构外，前ELH还包含其他几种分泌肽：AP（酸性肽）和α-、β-、γ-袋状细胞肽（BCPs）。BCPs长度为5至9个氨基酸，结构相似，因为它们都包含Arg-Leu-Arg-Phe序列。来自心房腺的另一种肽Atrial A也包含该序列。先前有报道称，BCPs对袋状细胞有直接反馈（自分泌）作用，包括电生理兴奋和抑制。此外，其中一些作用是温度依赖性的。通过研究这些肽对袋状细胞cAMP水平的影响，探索了它们的自分泌功能。此外，我们监测了Atrial A以及ELH和AP的作用，ELH和AP是前ELH的产物，与BCPs没有序列同源性。虽然ELH和AP对袋状细胞cAMP水平没有影响，但其他肽可分为两个功能类别。α-和γ-BCP在20摄氏度时使cAMP水平升高，在15摄氏度时使其降低。cAMP的升高对低Ca2+/高Mg2+敏感。β-BCP和Atrial A使cAMP水平升高，与温度无关，且对低Ca2+/高Mg2+不敏感。我们的结果表明，这些具有Arg-Leu-Arg-Phe序列的肽可能有多个袋状细胞受体，该序列代表一个受体识别基序。
