Protein 4.1 expression in the developing hair cells of the mouse inner ear.
Protein 4.1 (band 4.1 or 4.1R) was originally identified as an abundant protein of the human erythrocyte, in which it stabilizes the spectrin/actin cytoskeleton. Subsequently, several new family members, 4.1N, 4.1G and 4.1B, have been identified, which are expressed in many cell types, in particular at cell-cell junctions. We previously reported that 4.1R and 4.1N are expressed in the inner ear hair cells with specific localization patterns, and that 4.1R forms a complex with the membrane-associated guanylate kinase (MAGUK) protein p55 and two deafness gene products, myosin XV and whirlin. To determine the functions of the other family members, 4.1G and 4.1B, we observed their expression patterns in developing stereocilia in mice inner ear hair cells. 4.1G is expressed in the basal tapers of the stereocilia bundle in early postnatal stages. 4.1B was specifically and constantly expressed in the stereocilia tips during postnatal development. Additionally, we found that 4.1B is ablated in the hair cells of both myosin XV and whirlin mutant mice at all stages in hair cell development. These results suggest that 4.1 family members play important roles in the development and maintenance of the inner ear hair cells, and that 4.1B may be a member of the myosin XV-whirlin complex that is important for stereocilia maturation.
Department of Bioproduction, Tokyo University of Agriculture, 196, Yasaka, Abashiri, Hokkaido 099-2493, Japan.
Kazuhiro
K
Okumura
Eiji
E
Mochizuki
Michinari
M
Yokohama
Hisashi
H
Yamakawa
Hiroshi
H
Shitara
Philomena
P
Mburu
Hiromichi
H
Yonekawa
Steve D M
SD
Brown
Yoshiaki
Y
Kikkawa
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D007758:Ear, Inner / Q000166:cytology* / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D006199:Hair Cells, Auditory, Inner / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D008817:Mice, Mutant Strains; D008840:Microfilament Proteins; D009154:Mutation / Q000235:genetics; D009218:Myosins / Q000235:genetics
D003598:Cytoskeletal Proteins; C540651:Epb4.1l2 protein, mouse; C488402:Epb41l3 protein, mouse; D008565:Membrane Proteins; D008840:Microfilament Proteins; C114013:Myo15 protein, mouse; C477218:Whrn protein, mouse; D009218:Myosins