PubMed Journals: Gene
Source: PMID: 12527193
⇦ ⇨ Gene. 2003 Jan 2;302(1-2):21-9.
Mammalian Crumbs3 is a small transmembrane
protein linked to protein associated with
Makarova O(1), Roh MH, Liu CJ, Laurinec
S, Margolis B.
(1) Howard Hughes Medical Institute,
University of Michigan Medical School,
4570 MSRB II, Box 0650, 1150 W. Medical
Center Drive, Ann Arbor, MI 48109-0650,
Drosophila Crumbs is a transmembrane protein
that plays an important role in epithelial
cell polarity and photoreceptor development.
Overexpression of Crumbs in Drosophila epithelia
expands the apical surface and leads to
disruption of cell polarity. Drosophila
Crumbs also interacts with two other polarity
genes, Stardust and Discs Lost. Recent work
has identified a human orthologue of Drosophila
Crumbs, known as CRB1, that is mutated in
the eye disorders, retinitis pigmentosa
and Leber congenital amaurosis. Our work
has demonstrated that human CRB1 can form
a complex with mammalian orthologues of
Stardust and Discs Lost, known as protein
associated with Lin-7 (Pals1) and Pals1
associated tight junction (PATJ), respectively.
In the current report we have cloned a full
length cDNA for a human paralogue of CRB1
called Crumbs3 (CRB3). In contrast to Drosophila
Crumbs and CRB1, CRB3 has a very short extracellular
domain but like these proteins it has a
conserved intracellular domain that allows
it to complex with Pals1 and PATJ. Mouse
and human CRB3 have identical intracellular
domains but divergent extracellular domains
except for a conserved N-glycosylation site.
CRB3 is localized to the apical surface
and tight junctions but the conserved N
linked glycosylation site does not appear
to be necessary for CRB3 apical targeting.
CRB3 is a specialized isoform of the Crumbs
protein family that is expressed in epithelia
and can tie the apical membrane to the tight
PMID: 12527193 [Indexed for MEDLINE]