Journal of Cell Science, Vol 112, Issue 22 4089-4100, Copyright © 1999 by Company of Biologists

JOURNAL ARTICLES

The majority of clathrin coated vesicles from lactating rabbit mammary gland arises from the secretory pathway

A Pauloin, SA Tooze, I Michelutti, S Delpal and M Ollivier-Bousquet
INRA, Laboratoire de Biologie Cellulaire et Moleculaire, France. pauloin@biotec.jouy.inra.fr

Clathrin coated vesicles were isolated from lactating rabbit mammary gland by differential centrifugation, centrifugation on (2)H2O-sucrose cushions and Sephacryl S-1000 chromatography. Mammary epithelial cells contain an unexpectedly high quantity of clathrin coated vesicles which appear heterogeneous in size, with a mean diameter of 95.9+/-10.5 nm and a density of 1.23 g x ml(-1). Analysis of clathrin coated vesicle adaptor composition by SDS-PAGE and western blot showed that only approximately 5-10% of total APs consist of AP-2 in isolated mammary gland clathrin coated vesicles whereas it represents approximately 70% of the total APs from bovine brain clathrin coated vesicles. Cargo molecules known to be transcytosed such as IgG, IgA, and the pIgR were detected in the clathrin coated vesicles, indicating that part of this vesicle population is involved in transcytotic pathways. However, as the vast majority of the clathrin coated vesicles contained AP-1, it was likely that these clathrin coated vesicles were involved in the secretory pathway. Relatively high quantities of furin and cation-independent mannose 6-phosphate receptor were detected in mammary clathrin coated vesicles. By immuno electron microscopy, AP-1 and the cation-independent mannose 6-phosphate receptor were localized in Golgi-associated vesicles and on the membrane of secretory vesicles. The presence of AP-1 in the coat patches on the membrane of secretory vesicles containing casein micelles, and the presence of alpha(s1)-casein in mammary gland clathrin coated vesicles, support a role for AP-1 in the maturation of secretory vesicles. Our data pinpoint the importance of clathrin coated vesicles in lactating mammary epithelial cells, and suggest these vesicles are involved in the transcytotic pathway, in sorting at the trans-Golgi network and in the biogenesis of casein-containing secretory vesicles.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				J. J. Park and Y. P. Loh Minireview: How Peptide Hormone Vesicles Are Transported to the Secretion Site for Exocytosis Mol. Endocrinol., December 1, 2008; 22(12): 2583 - 2595. [Abstract] [Full Text] [PDF]

				P. A. Ortiz cAMP increases surface expression of NKCC2 in rat thick ascending limbs: role of VAMP Am J Physiol Renal Physiol, March 1, 2006; 290(3): F608 - F616. [Abstract] [Full Text] [PDF]

				M. A. Ellis, M. T. Miedel, C. J. Guerriero, and O. A. Weisz ADP-ribosylation Factor 1-independent Protein Sorting and Export from the trans-Golgi Network J. Biol. Chem., December 10, 2004; 279(50): 52735 - 52743. [Abstract] [Full Text] [PDF]

				I. Hinners and S. A. Tooze Changing directions: clathrin-mediated transport between the Golgi and endosomes J. Cell Sci., March 1, 2003; 116(5): 763 - 771. [Abstract] [Full Text] [PDF]

				H. M. Ngo, M. Yang, K. Paprotka, M. Pypaert, H. Hoppe, and K. A. Joiner AP-1 in Toxoplasma gondii Mediates Biogenesis of the Rhoptry Secretory Organelle from a Post-Golgi Compartment J. Biol. Chem., February 7, 2003; 278(7): 5343 - 5352. [Abstract] [Full Text] [PDF]