title: Structure and activity of OK-GC: a kidney receptor guanylate cyclase activated by guanylin peptides.
abstract: Uroguanylin, guanylin, and lymphoguanylin are small peptides that activate renal and intestinal receptor guanylate cyclases (GC). They are structurally similar to bacterial heat-stable enterotoxins (ST) that cause secretory diarrhea. Uroguanylin, guanylin, and ST elicit natriuresis, kaliuresis, and diuresis by direct actions on kidney GC receptors. A 3,762-bp cDNA characterizing a uroguanylin/guanylin/ST receptor was isolated from opossum kidney (OK) cell RNA/cDNA. This kidney cDNA (OK-GC) encodes a mature protein containing 1,049 residues sharing 72.4-75.8% identity with rat, human, and porcine forms of intestinal GC-C receptors. COS or HEK-293 cells expressing OK-GC receptor protein were activated by uroguanylin, guanylin, or ST13 peptides. The 3.8-kb OK-GC mRNA transcript is most abundant in the kidney cortex and intestinal mucosa, with lower mRNA levels observed in urinary bladder, adrenal gland, and myocardium and with no detectable transcripts in skin or stomach mucosa. We propose that OK-GC receptor GC participates in a renal mechanism of action for uroguanylin and/or guanylin in the physiological regulation of urinary sodium, potassium, and water excretion. This renal tubular receptor GC may be a target for circulating uroguanylin in an endocrine link between the intestine and kidney and/or participate in an intrarenal paracrine mechanism for regulation of kidney function via the intracellular second messenger, cGMP.
authors.affiliation: Department of Pharmacology, School of Medicine, Missouri University, Columbia, Missouri 65212, USA. LondonR@health.missouri.edu
authors.forename: R M
authors.initials: RM
authors.lastname: London
authors.forename: S L
authors.initials: SL
authors.lastname: Eber
authors.forename: S S
authors.initials: SS
authors.lastname: Visweswariah
authors.forename: W J
authors.initials: WJ
authors.lastname: Krause
authors.forename: L R
authors.initials: LR
authors.lastname: Forte
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D019556:COS Cells; D002460:Cell Line; D004789:Enzyme Activation / Q000502:physiology; D005768:Gastrointestinal Hormones; D006162:Guanylate Cyclase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D008969:Molecular Sequence Data; D045265:Natriuretic Peptides; D009893:Opossums; D010446:Peptide Fragments / Q000502:physiology*; D010455:Peptides / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; D018000:Receptors, Peptide / Q000378:metabolism; D013329:Structure-Activity Relationship; D014018:Tissue Distribution / Q000502:physiology
chemical_list: D005768:Gastrointestinal Hormones; D045265:Natriuretic Peptides; D010446:Peptide Fragments; D010455:Peptides; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D018000:Receptors, Peptide; C072685:guanylin; C084362:uroguanylin; D006162:Guanylate Cyclase; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled