TY - JOUR
T1 - Defective calmodulin-dependent rapid apical endocytosis in zebrafish sensory hair cell mutants
AU - Seiler, Christoph
AU - Nicolson, Teresa
PY - 1999/11/15
Y1 - 1999/11/15
N2 - Vertebrate mechanosensory hair cells contain a narrow 'pericuticular' zone which is densely populated with small vesicles between the cuticular plate and cellular junctions near the apical surface. The presence of many cytoplasmic vesicles suggests that the apical surface of hair cells has a high turnover rate. The significance of intense membrane trafficking at the apical surface is not known. Using a marker of endocytosis, the styryl dye FM1-43, this report shows that rapid apical endocytosis in zebrafish lateral line sensory hair cells is calcium and calmodulin dependent and is partially blocked by the presence of amiloride and dihydrostreptomycin, known inhibitors of mechanotransduction channels. As seen in lateral line hair cells, sensory hair cells within the larval otic capsule also exhibit rapid apical endocytosis. Defects in internalization of the dye in both lateral line and inner ear hair cells were found in five zebrafish auditory/vestibular mutants: sputnik, mariner, orbiter, mercury, and skylab. In addition, lateral line hair cells in these mutants were not sensitive to prolonged exposure to streptomycin, which is toxic to hair cells. The presence of endocytic defects in the majority of zebrafish mechanosensory mutants points to a important role of apical endocytosis in hair cell function.
AB - Vertebrate mechanosensory hair cells contain a narrow 'pericuticular' zone which is densely populated with small vesicles between the cuticular plate and cellular junctions near the apical surface. The presence of many cytoplasmic vesicles suggests that the apical surface of hair cells has a high turnover rate. The significance of intense membrane trafficking at the apical surface is not known. Using a marker of endocytosis, the styryl dye FM1-43, this report shows that rapid apical endocytosis in zebrafish lateral line sensory hair cells is calcium and calmodulin dependent and is partially blocked by the presence of amiloride and dihydrostreptomycin, known inhibitors of mechanotransduction channels. As seen in lateral line hair cells, sensory hair cells within the larval otic capsule also exhibit rapid apical endocytosis. Defects in internalization of the dye in both lateral line and inner ear hair cells were found in five zebrafish auditory/vestibular mutants: sputnik, mariner, orbiter, mercury, and skylab. In addition, lateral line hair cells in these mutants were not sensitive to prolonged exposure to streptomycin, which is toxic to hair cells. The presence of endocytic defects in the majority of zebrafish mechanosensory mutants points to a important role of apical endocytosis in hair cell function.
KW - Endocytosis
KW - FMI-43
KW - Ototoxicity
KW - Sensory hair cells
KW - Zebrafish
UR - http://www.scopus.com/inward/record.url?scp=0033571297&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033571297&partnerID=8YFLogxK
U2 - 10.1002/(SICI)1097-4695(19991115)41:3<424::AID-NEU10>3.0.CO;2-G
DO - 10.1002/(SICI)1097-4695(19991115)41:3<424::AID-NEU10>3.0.CO;2-G
M3 - Article
C2 - 10526320
AN - SCOPUS:0033571297
SN - 0022-3034
VL - 41
SP - 424
EP - 434
JO - Journal of Neurobiology
JF - Journal of Neurobiology
IS - 3
ER -