Functional characterization of Pactolus, a beta-integrin-like protein preferentially expressed by neutrophils.
Murine Pactolus is a beta-integrin-like molecule expressed exclusively on the surface of granulocytes. Cell surface expression of Pactolus is dramatically increased following activation of bone marrow neutrophils with known agonists, and cross-linking of cell surface Pactolus, suggesting the bulk of the protein is in intracellular stores. The mature protein is found in two forms depending upon the extent of N-linked glycosylation. There is no evidence to suggest that Pactolus requires an associated alpha chain for expression. In some mouse strains, a truncated form of the protein is predicted based upon alternative splicing: this form, however, is unstable and rapidly degraded after synthesis. Differences in the quantities of these Pactolus mRNA isoforms have defined two alleles. BALB/c and C3H/HeJ mice possess allele B and preferentially express the truncated, unstable product, whereas C57BL/6 mice possess allele A and only produce the membrane-bound form. Sequence analysis has shown the difference between these two alleles is due to a single base pair difference at the splice acceptor site for the truncated product. The increased expression of the membrane form of Pactolus by granulocytes of C57BL/6 mice suggests a compensatory adhesion function that is reduced in cells from the low producing strains.
Garrison
S
S
Division of Cell Biology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA.
Hojgaard
A
A
Patillo
D
D
Weis
J J
JJ
Weis
J H
JH
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA; D017931:DNA Primers; D006031:Glycosylation; D019012:Integrin beta1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016023:Integrins / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics
D017931:DNA Primers; D019012:Integrin beta1; D016023:Integrins; D012333:RNA, Messenger; C111859:pactolus; D004247:DNA