Cytoplasmic Domain of Natriuretic Peptide Receptor C Constitutes Gi Activator Sequences That Inhibit Adenylyl Cyclase Activity (2001)

We have recently demonstrated that a 37-amino acid peptide corresponding to the cytoplasmic domain of the natriuretic peptide receptor C (NPR-C) inhibited adenylyl cyclase activity via pertussis toxin (PT)-sensitive Gi protein. In the present studies, we have used seven different peptide fragments of the cytoplasmic domain of the NPR-C receptor with complete, partial, or no Gi activator sequence to examine their effects on adenylyl cyclase activity. The peptides used were KKYRITIERRNH (peptide 1), RRNHQEESNIGK (peptide 2), HRELREDSIRSH (peptide 3), RRNHQEESNIGKHRELR (peptide 4), QEESNIGK (peptide X), ITIERRNH (peptide Y), and ITIYKKRRNHRE (peptide Z). Peptides 1, 3, and 4 have complete Gi activator sequences, whereas peptides 2 and Y have partial Gi activator sequences with truncated carboxyl or amino terminus, respectively. Peptide X has no structural specificity, whereas peptide Z is the scrambled peptide control for peptide 1. Peptides 1, 3, and 4 inhibited adenylyl cyclase activity in a concentration-dependent manner with apparentKi between 0.1 and 1 nm; however, peptide 2 inhibited adenylyl cyclase activity with a higherKi of about 10 nm, and peptides X, Y, and Z were unable to inhibit adenylyl cyclase activity. The maximal inhibitions observed were between 30 and 40%. The inhibition of adenylyl cyclase activity by peptides 1–4 was absolutely dependent on the presence of guanine nucleotides and was completely attenuated by PT treatment. In addition, the stimulatory effects of isoproterenol, glucagon, and forskolin on adenylyl cyclase activity were inhibited to different degrees by these peptides. These results suggest that the small peptide fragments of the cytoplasmic domain of the NPR-C receptor containing 12 or 17 amino acids were sufficient to inhibit adenylyl cyclase activity through a PT-sensitive Gi protein. The peptides having complete structural specificity of Giactivator sequences at both amino and carboxyl termini were more potent to inhibit adenylyl cyclase activity as compared with the peptides having a truncated carboxyl terminus, whereas the truncation of the amino-terminal motif completely attenuates adenylyl cyclase inhibition. We have recently demonstrated that a 37-amino acid peptide corresponding to the cytoplasmic domain of the natriuretic peptide receptor C (NPR-C) inhibited adenylyl cyclase activity via pertussis toxin (PT)-sensitive Gi protein. In the present studies, we have used seven different peptide fragments of the cytoplasmic domain of the NPR-C receptor with complete, partial, or no Gi activator sequence to examine their effects on adenylyl cyclase activity. The peptides used were KKYRITIERRNH (peptide 1), RRNHQEESNIGK (peptide 2), HRELREDSIRSH (peptide 3), RRNHQEESNIGKHRELR (peptide 4), QEESNIGK (peptide X), ITIERRNH (peptide Y), and ITIYKKRRNHRE (peptide Z). Peptides 1, 3, and 4 have complete Gi activator sequences, whereas peptides 2 and Y have partial Gi activator sequences with truncated carboxyl or amino terminus, respectively. Peptide X has no structural specificity, whereas peptide Z is the scrambled peptide control for peptide 1. Peptides 1, 3, and 4 inhibited adenylyl cyclase activity in a concentration-dependent manner with apparentKi between 0.1 and 1 nm; however, peptide 2 inhibited adenylyl cyclase activity with a higherKi of about 10 nm, and peptides X, Y, and Z were unable to inhibit adenylyl cyclase activity. The maximal inhibitions observed were between 30 and 40%. The inhibition of adenylyl cyclase activity by peptides 1–4 was absolutely dependent on the presence of guanine nucleotides and was completely attenuated by PT treatment. In addition, the stimulatory effects of isoproterenol, glucagon, and forskolin on adenylyl cyclase activity were inhibited to different degrees by these peptides. These results suggest that the small peptide fragments of the cytoplasmic domain of the NPR-C receptor containing 12 or 17 amino acids were sufficient to inhibit adenylyl cyclase activity through a PT-sensitive Gi protein. The peptides having complete structural specificity of Giactivator sequences at both amino and carboxyl termini were more potent to inhibit adenylyl cyclase activity as compared with the peptides having a truncated carboxyl terminus, whereas the truncation of the amino-terminal motif completely attenuates adenylyl cyclase inhibition. rat atrial natriuretic peptide (28 amino acids) brain natriuretic peptide C-type natriuretic peptide [des-Gln18,Ser19,Gly20,Leu21,Gly22]rat ANP-(4–23) natriuretic peptide receptor pertussis toxin guanosine 5′-3-O-(thio)triphosphate Atrial natriuretic peptide (ANP),1 a member of the family of natriuretic peptides (NP), discovered by de Bold et al. (1de Bold A.J. Borenstein H.B. Veress A.T. Sonnenberg H. 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Kangawa K. Matsuo H. Biochem. Biophys. Res. Commun. 1990; 168: 863-870Crossref PubMed Scopus (967) Google Scholar). The role played by ANP and BNP as endocrine hormones is apparently to be antagonists to vasopressin, endothelins, and the renin-angiotensin-aldosterone system (12Brenner B.M. Ballarman B.J. Gunning M.E. Zeidel M.L. Physiol. Rev. 1990; 70: 665-699Crossref PubMed Scopus (855) Google Scholar, 15Ruskoaho H. Pharmacol Rev. 1992; 44: 479-602PubMed Google Scholar). The role of CNPin vivo is less well defined. Although CNP might not be a significant modulator of diuresis and natriuresis (16Stingo A.J. Clavell A.L. Aarhus L.L. Burnett J.C. Am. J. Physiol. 1992; 262: H308-H312PubMed Google Scholar, 17Clavell A.L. Stingo A.J. Wei C.M. Heublein D.M. Burnett J.C. Am. J. Physiol. 1993; 264: R290-R295PubMed Google Scholar), it is a vasodilator expressed by endothelial cells (14Sudoh T. Minamino N. Kangawa K. Matsuo H. Biochem. Biophys. Res. Commun. 1990; 168: 863-870Crossref PubMed Scopus (967) Google Scholar, 18Suga S. Nakao K. Itoh H. Komatsu Y. Ogawa Y. Hama N. Imura H. J. Clin. Invest. 1992; 90: 1145-1190Crossref PubMed Scopus (493) Google Scholar). Compared with ANP, BNP has an additional six-amino acid sequence at its amino-terminal end (5Anand-Srivastava M.B. Vinay P. Genest J. Cantin M. Am. J. Physiol. 1986; 251: F417-F423PubMed Google Scholar, 13Sudoh T. Kangawa K. Minamino N. Matsuo H. Nature. 1988; 332: 78-81Crossref PubMed Scopus (1626) Google Scholar, 19Kambayashi Y. Nakao K. Mukoyama M. Saito Y. Ogawa Y. Shiono S. Inouye K. Yoshida N. Imura H. FEBS Lett. 1990; 259: 341-345Crossref PubMed Scopus (219) Google Scholar), whereas CNP lacks the carboxyl-terminal extension. (14Sudoh T. Minamino N. Kangawa K. Matsuo H. Biochem. Biophys. Res. Commun. 1990; 168: 863-870Crossref PubMed Scopus (967) Google Scholar). Molecular cloning techniques revealed three subtypes of natriuretic peptide receptors (NPR): NPR-A (20Chinkers M. Garbers D.L. Chang M-S. Lowe D.G. Chin H. Goeddel D.V. Schulz S. Nature. 1989; 338: 78-83Crossref PubMed Scopus (887) Google Scholar, 21Lowe D.G. Chang M.S. Hellmiss R. Chen E. Singh S. Garbers D.L. Goeddel D.V. EMBO J. 1989; 8: 1377-1384Crossref PubMed Scopus (315) Google Scholar), NPR-B (22Schulz S. Singh S. Bellet R.A. Singh G. Tubb D.J. Chin H. Garbers D.L. Cell. 1989; 58: 1155-1162Abstract Full Text PDF PubMed Scopus (491) Google Scholar, 23Chang M.S. Lowe D.G. Lewis M. Hellmiss R. Chen E. Goeddel D.V. Nature. 1989; 341: 68-72Crossref PubMed Scopus (501) Google Scholar), and NPR-C (24Fuller F. Porter J.G. Arfsten A.E. Miller J. Schilling J.W. Scarborough R.M. Lewicki J.A. Schenk D.B. J. Biol. Chem. 1988; 263: 9395-9401Abstract Full Text PDF PubMed Google Scholar,25Anand-Srivastava M.B. Srivastava A.K. Cantin M. J. Biol. Chem. 1987; 262: 4931-4934Abstract Full Text PDF PubMed Google Scholar). NPR-A and NPR-B are membrane guanylyl cyclases, whereas NPR-C (clearance receptor) lacks guanylyl cyclase activity. NPR-A catalyzes the production of cGMP in response to ANP and BNP, whereas NPR-B is the target for CNP. NPR-C receptors on the other hand are coupled to adenylyl cyclase inhibition through inhibitory guanine nucleotide-regulatory protein (25Anand-Srivastava M.B. Srivastava A.K. Cantin M. J. Biol. Chem. 1987; 262: 4931-4934Abstract Full Text PDF PubMed Google Scholar, 26Anand-Srivastava M.B. Sairam M.R. Cantin M. J. Biol. Chem. 1990; 265: 8566-8572Abstract Full Text PDF PubMed Google Scholar) or to activation of phospholipase C (27Hirata M. Chang C.H. Murad F. Biochim. Biophys. Acta. 1989; 1010: 346-351Crossref PubMed Scopus (141) Google Scholar). NPR-C receptors are disulfide-linked homodimers of 64–66 kDa, having a single transmembrane domain (24Fuller F. Porter J.G. Arfsten A.E. Miller J. Schilling J.W. Scarborough R.M. Lewicki J.A. Schenk D.B. J. Biol. Chem. 1988; 263: 9395-9401Abstract Full Text PDF PubMed Google Scholar, 28Schenk D.B. Phelps M.N. Porter J.G. Scarborough R.M. McEnroe G.A. Lewicki J.A. J. Biol. Chem. 1985; 260: 14887-14890Abstract Full Text PDF PubMed Google Scholar, 29Leitman D.C. Andersen J.W. Catalano R.M. Waldman S.A. Tuan J.J. Murad R. J. Biol. Chem. 1988; 263: 3720-3728Abstract Full Text PDF PubMed Google Scholar), an extracellular domain of ∼440 amino acids, and a short 37-amino acid cytoplasmic domain or tail. We have recently demonstrated that the 37-amino acid peptide (R37A) corresponding to the cytoplasmic domain of the NPR-C receptor inhibited adenylyl cyclase activity in rat heart particulate fractions, which was completely blocked by the polyclonal rabbit antisera raised against R37A (30Anand-Srivastava M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar). The inhibition was dependent on the presence of GTP and was blocked by pertussis toxin (PT) treatment. Furthermore, inhibition of adenylyl cyclase by R37A was not due to the positive charges, because a scrambled peptide K37A with the same composition as that of R37A but a different sequence did not inhibit adenylyl cyclase activity (30Anand-Srivastava M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar). These data suggested that certain structural specificity present in the cytoplasmic domain of the NPR-C receptor may be responsible for exerting inhibitory effects on adenylyl cyclase. Okamoto et al. (31Okamoto T. Nishimoto I. J. Biol. Chem. 1992; 267: 8342-8346Abstract Full Text PDF PubMed Google Scholar) have shown that a short intracellular region of 14 amino acids (Arg2410–Lys2423) of insulin-like growth factor II receptor having a specific Giactivator sequence was able to activate Gi protein directly in the same manner as that of conventional Gi-coupled receptors. This sequence (Gi activator) was characterized by the presence of two basic amino acids at the NH2terminus and BBXB or BBXXB at the COOH terminus, where B and X denote basic amino acid and nonbasic amino acid, respectively. The cytoplasmic domain of NPR-C receptor contains several of these Gi activator sequences. In the present studies, we have used seven different synthetic peptide fragments of the cytoplasmic domain of NPR-C receptor with complete, partial, or no Gi activator sequence in order to examine their effects on adenylyl cyclase activity. We have shown that small fragment peptides of the cytoplasmic domain of the NPR-C receptor with complete Gi activator sequence were more potent inhibitors of adenylyl cyclase activity, compared with the peptides having partial or no consensus Gi activator sequence. ATP, cAMP, and isoproterenol were purchased from Sigma. Creatine kinase (EC 2.7.4.3) and GTPγS were purchased fromRoche Molecular Biochemicals. [α-32P]ATP was purchased from Amersham Pharmacia Biotech. Pertussis toxin was from List Biochemicals (Campbell, CA). Rat ANP, a ring-deleted analog of ANP, and II were from CA). Peptides 1, 3, X, Y, and Z were by techniques and by and were from in and at were to a with a and in The heart was a in a containing 10 and 1 and at for 10 The was and the was in the and at for 10 The was by in 10 and 1 and used directly for adenylyl cyclase activity was as A.L. J. Biol. Chem. Full Text PDF PubMed Google Scholar) with as a The from of rat was from the The cells were in and at in a and in and containing and The cells were with containing and between and The cells were a and by at 4 for 10 at The cells were in a and the was used for an adenylyl cyclase PT was as (25Anand-Srivastava M.B. Srivastava A.K. Cantin M. J. Biol. Chem. 1987; 262: 4931-4934Abstract Full Text PDF PubMed Google Scholar, M.B. Gutkowska J. Cantin M. Biochem. J. PubMed Scopus Google Scholar, M.B. Biochem. J. 1992; 288: PubMed Scopus Google Scholar). heart particulate were in containing 1 ATP, 10 and with and PT for 30 at 30 The particulate was two to three with 10 1 and in the same and used for adenylyl cyclase activity of the at 30 for 30 in the or presence of PT in a significant of activity which was of the presence of PT in the the inhibition of adenylyl cyclase activity by the different peptides used cyclase activity was by from [α-32P]ATP as M.B. Sairam M.R. Cantin M. J. Biol. Chem. 1990; 265: 8566-8572Abstract Full Text PDF PubMed Google Scholar, M.B. Gutkowska J. Cantin M. Biochem. J. PubMed Scopus Google Scholar). The [α-32P]ATP cAMP, 1 0.1 10 and an system of 2 0.1 of in a of were with the of to the which at for 10 The in at for 10 were by the of of and was by of other nucleotides with by the of of by the system Y. C. M. Biochem. 58: PubMed Scopus Google Scholar). these adenylyl cyclase activity was with to protein and of The 37-amino acid peptide (R37A) corresponding to the cytoplasmic domain of the NPR-C receptor has shown to inhibit adenylyl cyclase activity by interacting directly with Gi (30Anand-Srivastava M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar). In order to the small peptide fragments of the cytoplasmic domain that of partial or complete Gi activator sequences the of R37A or ANP on NPR-C inhibition of adenylyl seven different synthetic peptides were used to examine their effects on adenylyl cyclase activity. The peptide fragments different of the cytoplasmic domain as shown in 1. These of 12 amino acids 1, 3, and 17 amino acids (peptide 4), or amino acids X and Peptides 1, 3, and 4 the Gi activator two basic amino acids at the and or BBXXB at the COOH terminus, B a basic amino acid and X a nonbasic amino whereas peptide 2 has two basic amino acids at the NH2terminus but not have the consensus sequence at the COOH the other peptide Y has the consensus sequence at the COOH terminus, and peptide X lacks Gi activator whereas peptide Z is the scrambled peptide and as control for peptide 1. 2 that peptides 1, 3, and 4 of the cytoplasmic domain of the NPR-C receptor at inhibited adenylyl cyclase activity by and in rat heart particulate In addition, and as (3Anand-Srivastava M.B. Franks D.J. Cantin M. Genest J. Biochem. Biophys. Res. Commun. 1984; 121: 855-862Crossref PubMed Scopus (132) Google Scholar, 26Anand-Srivastava M.B. Sairam M.R. Cantin M. J. Biol. Chem. 1990; 265: 8566-8572Abstract Full Text PDF PubMed Google M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar, A. C. Anand-Srivastava M.B. Biochem. Biophys. PubMed Scopus Google Scholar), inhibited the activity by about peptides X, Y, and Z did not inhibit adenylyl cyclase activity. results were observed in cells however, the inhibitions were in these These results suggest that small peptides of the cytoplasmic domain of the NPR-C receptor with 12 amino acids or more with specific Gi activator sequence inhibit adenylyl cyclase activity. the effects of of the seven peptides on adenylyl cyclase activity in heart particulate Peptides 1, 3, and 4 inhibited adenylyl cyclase activity in a concentration-dependent manner with between 0.1 and 1 nm; however, peptide 2 inhibited adenylyl cyclase activity with a higherKi of about 10 The maximal inhibitions of adenylyl cyclase activity by peptides 1, 3, and 4 were about and respectively. The inhibitory of these peptides was not due to the positive because the scrambled peptide (peptide of peptide 1 that has the same amino acid composition was unable to inhibitory on adenylyl cyclase. In addition, peptides X and Y did not inhibit adenylyl cyclase activity. These data suggest that the peptides the Gi activator sequence at the carboxyl as well as at the amino are more potent inhibitors of adenylyl cyclase activity the peptides having partial or no structural The inhibitory of the R37A peptide corresponding to the cytoplasmic domain of the NPR-C receptor on adenylyl cyclase activity has to be dependent on the presence of guanine nucleotides (30Anand-Srivastava M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar). In order to the inhibition of adenylyl cyclase by the small peptides guanine the of different peptides on adenylyl cyclase activity in the or presence of GTPγS was The results shown in that peptides did not inhibitory on adenylyl cyclase in the of however, in the presence of of the peptides inhibited the activity in a concentration-dependent The maximal inhibitions was observed at 10 These results that the inhibition of adenylyl cyclase by peptides of the cytoplasmic domain of NPR-C is dependent on the presence of guanine The of NPR-C receptors to cyclase through Gi has demonstrated (25Anand-Srivastava M.B. Srivastava A.K. Cantin M. J. Biol. Chem. 1987; 262: 4931-4934Abstract Full Text PDF PubMed Google Scholar, M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar). Furthermore, we have shown that R37A inhibited adenylyl cyclase through a PT-sensitive Gi protein. examine the inhibition of adenylyl cyclase by these peptides is through the of PT on the inhibitory effects of the peptides on adenylyl cyclase activity was that peptides inhibited the activity in a concentration-dependent manner in control heart particulate fractions, which was attenuated by PT treatment. These results the small peptides of the cytoplasmic domain of NPR-C receptor inhibit adenylyl cyclase through a PT-sensitive Gi protein. and as well as R37A peptide have shown to inhibit the stimulatory effects of on adenylyl cyclase activity (25Anand-Srivastava M.B. Srivastava A.K. Cantin M. J. Biol. Chem. 1987; 262: 4931-4934Abstract Full Text PDF PubMed Google Scholar, 26Anand-Srivastava M.B. Sairam M.R. Cantin M. J. Biol. Chem. 1990; 265: 8566-8572Abstract Full Text PDF PubMed Google Scholar, M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar), it was of to examine small peptides of the cytoplasmic domain of the NPR-C receptor are of the adenylyl cyclase activity in heart particulate shown in glucagon, isoproterenol, and forskolin adenylyl cyclase activity by about and which was inhibited by peptides to was inhibited by about whereas activity was inhibited by about and activity was inhibited by about We have shown that 37-amino acid synthetic peptide (R37A) corresponding to the cytoplasmic domain of NPR-C receptor inhibited adenylyl cyclase activity via PT-sensitive (30Anand-Srivastava M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar). In the present studies, we for the that the cytoplasmic domain peptide of NPR-C receptor has several Gi activator sequences that inhibit adenylyl cyclase activity in a manner via PT-sensitive Gi The small peptide fragments of the cytoplasmic domain of the NPR-C receptor containing 12 amino acids peptide with consensus sequence for Gi activation at both and COOH at the and the BBXB motif at the COOH inhibited adenylyl cyclase activity in rat heart particulate fractions, and The other peptide fragments containing 17 amino acids peptide with a consensus sequence of at the and BBXXB at the COOH inhibited adenylyl cyclase activity in these of these peptide fragments 1 and inhibited the activity in a concentration-dependent manner with an apparentKi between 0.1 and 1 nm, and the maximal inhibition observed was about The of these peptide fragments to inhibit adenylyl cyclase activity was in the same as that of the cytoplasmic domain peptide R37A as (30Anand-Srivastava M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar). The inhibitory of these peptides on adenylyl cyclase was not due to the positive present amino acid the scrambled peptide Z with the same composition as peptide 1 but the Gi activator sequence at the and COOH did not inhibit adenylyl cyclase activity. the other the presence of partial motif but motif in the peptide did not the of the peptide to inhibit adenylyl cyclase activity, that a partial motif in the peptide may be sufficient to inhibitory on adenylyl cyclase activity. the truncation of motif from peptide 2 inhibited adenylyl cyclase activity with that the motif may be to the of the peptides to adenylyl cyclase inhibition. These results are in with the of et al. S. Lowe D.G. Trachte G.J. PubMed Scopus Google Scholar), have shown that the acid peptide fragment of NPR-C receptor that lacks the motif attenuated in cells R37A peptide corresponding to the cytoplasmic domain of the NPR-C receptor that lacks the motif has to inhibit adenylyl cyclase activity (30Anand-Srivastava M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar) as well as S. Lowe D.G. Trachte G.J. PubMed Scopus Google Scholar). results are in with of and J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), have shown that the cytoplasmic domain peptide fragment of the NPR-C receptor that lacks the COOH was in phospholipase activity in and The truncation of the motif of peptide 2 results in of the peptide to inhibit adenylyl cyclase activity, that consensus sequence is to with Gi to inhibition of adenylyl cyclase. This is by results that peptide Y that has the consensus sequence at the COOH but lacks the sequence was unable to inhibit adenylyl cyclase activity. and J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) have shown that peptide containing the consensus sequence at the NH2terminus was unable to phospholipase in This may be to the in the system in the two these have shown that the acid peptide of the NPR-C receptor cytoplasmic domain phospholipase activity at with an of whereas we have shown that the of the peptides 1, 3, and 4 was at in adenylyl cyclase activity. In addition, peptide 2 that lacks the motif sequence was less peptides 1, 3, and 4 but was able to inhibit adenylyl cyclase activity, whereas and J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) did not of the peptide the consensus sequence on phospholipase activity. The of of peptide in their may be due to the that peptide did not have the consensus sequence and is to peptide X in studies, which was unable to inhibit adenylyl cyclase activity. it be suggested that the motif of these peptides may be the for the with Gi protein and to activate the on the on guanine nucleotides of adenylyl cyclase inhibition and its by PT are with (25Anand-Srivastava M.B. Srivastava A.K. Cantin M. J. Biol. Chem. 1987; 262: 4931-4934Abstract Full Text PDF PubMed Google Scholar, 26Anand-Srivastava M.B. Sairam M.R. Cantin M. J. Biol. Chem. 1990; 265: 8566-8572Abstract Full Text PDF PubMed Google Scholar, M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar) and suggest that the small peptide fragments of the cytoplasmic domain of NPR-C the cytoplasmic domain peptide inhibit adenylyl cyclase via PT-sensitive Gi protein. In addition, the inhibition of and of adenylyl cyclase by small peptides is with on ANP, and R37A and adenylyl cyclase (25Anand-Srivastava M.B. Srivastava A.K. Cantin M. J. Biol. Chem. 1987; 262: 4931-4934Abstract Full Text PDF PubMed Google Scholar, 26Anand-Srivastava M.B. Sairam M.R. Cantin M. J. Biol. Chem. 1990; 265: 8566-8572Abstract Full Text PDF PubMed Google Scholar, M.B. Sehl P.D. Lowe D.G. J. Biol. Chem. 1996; 271: 19324-19329Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar). In we have the to that the cytoplasmic domain peptides of the NPR-C receptor of 12 amino acids complete Gi activator sequence at the COOH and termini are sufficient to inhibit adenylyl cyclase activity through a PT-sensitive Gi protein with the same as that of the cytoplasmic domain whereas the peptides with a truncated COOH inhibited the activity with however, the truncation of the motif completely attenuates adenylyl cyclase inhibition. We for