The pro region is not required for the expression or intracellular routeing of carboxypeptidase E

Lixin Song, Lloyd D. Fricker

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Carboxypeptidase E (CPE) is initially synthesized as a larger precursor containing an additional l4-residue propeptide that is highly conserved between human and rat. Previous studies have established that the proenzyme is enzymically active and that deletion of the pro region does not affect the expression of the active enzyme. In the present study the function of the pro region was examined both by deleting this region from CPE and by attaching this region to the N-terminus of albumin. CPE lacking the pro region is sorted into the regulated secretory pathway in AtT-20 cells, based on confocal microscopy and examination of the stimulated secretion of the protein. Stimulation of AtT-20 cells with either forskolin or phorbol 12-myristate 13-acetate induces the secretion of wild-type CPE and of CPE lacking the pro region to similar extents, indicating a similar efficiency of sorting of the mutant. When the pro region of proalbumin is replaced with the pro region of CPE followed by expression in AtT-20 cells, the protein is not sorted into the regulated pathway, based on the lack of stimulated secretion. Confocal microscopy suggests that the proCPE/albumin protein is retained in the endoplasmic reticulum to a greater extent than is proalbumin. Pulse-chase analysis indicates that the pro region of CPE is not efficiently removed from the N-terminus of albumin, and the small amount of propeptide cleavage that does occur takes place soon before secretion of the protein. In contrast, confocal microscopy indicates that the majority of the propeptide is removed from CPE, and that this cleavage occurs in the trans-Golgi network or soon after sorting into the secretory vesicles. Taken together, these results suggest that the pro region of CPE is not required for the expression or intracellular routeing of this protein.

Original languageEnglish (US)
Pages (from-to)265-271
Number of pages7
JournalBiochemical Journal
Volume323
Issue number1
StatePublished - Apr 1 1997

Fingerprint

Carboxypeptidase H
Confocal microscopy
Confocal Microscopy
Albumins
Prealbumin
Proteins
Sorting
trans-Golgi Network
Enzyme Precursors
Secretory Pathway
Secretory Vesicles
Colforsin
Endoplasmic Reticulum
Rats
Acetates

ASJC Scopus subject areas

  • Biochemistry

Cite this

The pro region is not required for the expression or intracellular routeing of carboxypeptidase E. / Song, Lixin; Fricker, Lloyd D.

In: Biochemical Journal, Vol. 323, No. 1, 01.04.1997, p. 265-271.

Research output: Contribution to journalArticle

@article{a8c8e781747b4375a01bf72db0b4f83f,
title = "The pro region is not required for the expression or intracellular routeing of carboxypeptidase E",
abstract = "Carboxypeptidase E (CPE) is initially synthesized as a larger precursor containing an additional l4-residue propeptide that is highly conserved between human and rat. Previous studies have established that the proenzyme is enzymically active and that deletion of the pro region does not affect the expression of the active enzyme. In the present study the function of the pro region was examined both by deleting this region from CPE and by attaching this region to the N-terminus of albumin. CPE lacking the pro region is sorted into the regulated secretory pathway in AtT-20 cells, based on confocal microscopy and examination of the stimulated secretion of the protein. Stimulation of AtT-20 cells with either forskolin or phorbol 12-myristate 13-acetate induces the secretion of wild-type CPE and of CPE lacking the pro region to similar extents, indicating a similar efficiency of sorting of the mutant. When the pro region of proalbumin is replaced with the pro region of CPE followed by expression in AtT-20 cells, the protein is not sorted into the regulated pathway, based on the lack of stimulated secretion. Confocal microscopy suggests that the proCPE/albumin protein is retained in the endoplasmic reticulum to a greater extent than is proalbumin. Pulse-chase analysis indicates that the pro region of CPE is not efficiently removed from the N-terminus of albumin, and the small amount of propeptide cleavage that does occur takes place soon before secretion of the protein. In contrast, confocal microscopy indicates that the majority of the propeptide is removed from CPE, and that this cleavage occurs in the trans-Golgi network or soon after sorting into the secretory vesicles. Taken together, these results suggest that the pro region of CPE is not required for the expression or intracellular routeing of this protein.",
author = "Lixin Song and Fricker, {Lloyd D.}",
year = "1997",
month = "4",
day = "1",
language = "English (US)",
volume = "323",
pages = "265--271",
journal = "Biochemical Journal",
issn = "0264-6021",
publisher = "Portland Press Ltd.",
number = "1",

}

TY - JOUR

T1 - The pro region is not required for the expression or intracellular routeing of carboxypeptidase E

AU - Song, Lixin

AU - Fricker, Lloyd D.

PY - 1997/4/1

Y1 - 1997/4/1

N2 - Carboxypeptidase E (CPE) is initially synthesized as a larger precursor containing an additional l4-residue propeptide that is highly conserved between human and rat. Previous studies have established that the proenzyme is enzymically active and that deletion of the pro region does not affect the expression of the active enzyme. In the present study the function of the pro region was examined both by deleting this region from CPE and by attaching this region to the N-terminus of albumin. CPE lacking the pro region is sorted into the regulated secretory pathway in AtT-20 cells, based on confocal microscopy and examination of the stimulated secretion of the protein. Stimulation of AtT-20 cells with either forskolin or phorbol 12-myristate 13-acetate induces the secretion of wild-type CPE and of CPE lacking the pro region to similar extents, indicating a similar efficiency of sorting of the mutant. When the pro region of proalbumin is replaced with the pro region of CPE followed by expression in AtT-20 cells, the protein is not sorted into the regulated pathway, based on the lack of stimulated secretion. Confocal microscopy suggests that the proCPE/albumin protein is retained in the endoplasmic reticulum to a greater extent than is proalbumin. Pulse-chase analysis indicates that the pro region of CPE is not efficiently removed from the N-terminus of albumin, and the small amount of propeptide cleavage that does occur takes place soon before secretion of the protein. In contrast, confocal microscopy indicates that the majority of the propeptide is removed from CPE, and that this cleavage occurs in the trans-Golgi network or soon after sorting into the secretory vesicles. Taken together, these results suggest that the pro region of CPE is not required for the expression or intracellular routeing of this protein.

AB - Carboxypeptidase E (CPE) is initially synthesized as a larger precursor containing an additional l4-residue propeptide that is highly conserved between human and rat. Previous studies have established that the proenzyme is enzymically active and that deletion of the pro region does not affect the expression of the active enzyme. In the present study the function of the pro region was examined both by deleting this region from CPE and by attaching this region to the N-terminus of albumin. CPE lacking the pro region is sorted into the regulated secretory pathway in AtT-20 cells, based on confocal microscopy and examination of the stimulated secretion of the protein. Stimulation of AtT-20 cells with either forskolin or phorbol 12-myristate 13-acetate induces the secretion of wild-type CPE and of CPE lacking the pro region to similar extents, indicating a similar efficiency of sorting of the mutant. When the pro region of proalbumin is replaced with the pro region of CPE followed by expression in AtT-20 cells, the protein is not sorted into the regulated pathway, based on the lack of stimulated secretion. Confocal microscopy suggests that the proCPE/albumin protein is retained in the endoplasmic reticulum to a greater extent than is proalbumin. Pulse-chase analysis indicates that the pro region of CPE is not efficiently removed from the N-terminus of albumin, and the small amount of propeptide cleavage that does occur takes place soon before secretion of the protein. In contrast, confocal microscopy indicates that the majority of the propeptide is removed from CPE, and that this cleavage occurs in the trans-Golgi network or soon after sorting into the secretory vesicles. Taken together, these results suggest that the pro region of CPE is not required for the expression or intracellular routeing of this protein.

UR - http://www.scopus.com/inward/record.url?scp=0030906460&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030906460&partnerID=8YFLogxK

M3 - Article

C2 - 9173892

AN - SCOPUS:0030906460

VL - 323

SP - 265

EP - 271

JO - Biochemical Journal

JF - Biochemical Journal

SN - 0264-6021

IS - 1

ER -