Dictyostelium CBP3 associates with actin cytoskeleton and is related to slug migration.
Calcium-binding protein 3 (CBP3) expression was up-regulated under the control of the actin 15 promoter and down-regulated by RNA interference in Dictyostelium discoideum. The overexpression of CBP3 accelerated cell aggregation and formed small aggregates and fruiting body. CBP3-inhibited cells showed uneven aggregation and increased slug trail lengths toward the directed light, whereas CBP3-overexpressing cells showed the opposite phenomena. Under dark condition, the enhanced slug trail length was also observed in the CBP3-inhibited cells. Yeast two-hybrid screening identified actin 8 as interacting protein with CBP3. The interaction between CBP3 and actin was confirmed by beta-galactosidase assay and surface plasmon resonance. CBP3 was associated with Triton X-100-insoluble cytoskeleton in the presence of Ca(2+) and the interaction of CBP3 with cytoskeleton was increased by the addition of Ca(2+). Using fluorescence microscopy, CBP3 was also shown to associate with the actin cytoskeleton during development. Subcellular fractionation indicated that CBP3 was enriched in cytosolic fraction. Taken together, these results suggest that CBP3 interacts with actin cytoskeleton and has a role during cell aggregation and slug migration of Dictyostelium.
Lee
Chang-Hun
CH
School of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
Jeong
Sun-Young
SY
Kim
Beom-Jun
BJ
Choi
Chang-Hoon
CH
Kim
Ji-Sun
JS
Koo
Byung-Mo
BM
Seok
Young-Jae
YJ
Yim
Hyung-Soon
HS
Kang
Sa-Ouk
SO
D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D037282:Calreticulin / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D004023:Dictyostelium / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D034622:RNA Interference; D013347:Subcellular Fractions / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D000199:Actins; D037282:Calreticulin; D002118:Calcium