Kalirin, a Cytosolic Protein with Spectrin-like and GDP/GTP Exchange Factor-like Domains That Interacts with Peptidylglycine α-Amidating Monooxygenase, an Integral Membrane Peptide-processing Enzyme*
- M. Rashidul Alam,
- Richard C. Johnson,
- Daniel N. Darlington‡,
- Tracey A. Hand,
- Richard E. Mains and
- Betty A. Eipper§
- From the Departments of Neuroscience and Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 and the ‡Departments of Surgery and Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
Abstract
Although the integral membrane proteins that catalyze steps in the biosynthesis of neuroendocrine peptides are known to contain routing information in their cytosolic domains, the proteins recognizing this routing information are not known. Using the yeast two-hybrid system, we previously identified P-CIP10 as a protein interacting with the cytosolic routing determinants of peptidylglycine α-amidating monooxygenase (PAM). P-CIP10 is a 217-kDa cytosolic protein with nine spectrin-like repeats and adjacent Dbl homology and pleckstrin homology domains typical of GDP/GTP exchange factors. In the adult rat, expression of P-CIP10 is most prevalent in the brain. Corticotrope tumor cells stably expressing P-CIP10 and PAM produce longer and more highly branched neuritic processes than nontransfected cells or cells expressing only PAM. The turnover of newly synthesized PAM is accelerated in cells co-expressing P-CIP10. P-CIP10 binds to selected members of the Rho subfamily of small GTP binding proteins (Rac1, but not RhoA or Cdc42). P-CIP10 (kalirin), a member of the Dbl family of proteins, may serve as part of a signal transduction system linking the catalytic domains of PAM in the lumen of the secretory pathway to cytosolic factors regulating the cytoskeleton and signal transduction pathways.
Footnotes
-
↵* This work was supported by National Institutes of Health Grants DK-32949 and 32948.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵§ To whom correspondence should be addressed: 907 Wood Basic Science Bldg., The Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205-2105. Tel.: 410-955-6937; Fax: 410-955-0681; E-mail: betty.eipper{at}jhu.edu.
-
↵1 The abbreviations used are: PAM, peptidylglycine α-amidating monooxygenase; TGN, trans-Golgi network; kb, kilobase pair(s); RHP, RACE hybrid primer; PCR, polymerase chain reaction; pBS, pBluescript II (SK−); aa, amino acids; nt, nucleotide(s); DH, Dbl homology; PH, pleckstrin homology; PAGE, polyacrylamide gel electrophoresis; TES, 2-{[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]amino}ethanesulfonic acid; Ab, antibody; mAb, monoclonal antibody; EST, expressed sequence tag; GST, glutathione S-transferase; CD, cytosolic domain; LAR, leukocyte common antigen-related; MCS, multiple cloning site.
-
- Received February 3, 1997.
- Revision received March 5, 1997.
