Tue, Mar 10, 5:30-6:30 PM, 2015

Austin |  UT Austin, BME 1.112 
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Who Needs Steroid? 誰需要類固醇？

Dr. Jui-Hsia Weng 翁瑞霞博士 
Postdoctoral Fellow, Harvard Medical School 

We are pleased to have Dr. Jui-Hsia Weng come to our BTBA academic seminar series on March 10th (Tues) to share her work on Pregnenolone (neurosteroid) in zebrafish development. Hope to see you all there!

Abstract
Pregnenolone (P5) is a neurosteroid that improves memory and neurological recovery. It is also required for zebrafish embryonic development. However, its mode of action is unclear. Here I show that P5 promotes cell migration and microtubule polymerization by binding to a microtubule-plus-end-tracking cytoplasmic linker protein 1 (CLIP-170). CLIP-170 was captured from zebrafish embryonic extract by a P5 photoaffinity probe conjugated to diaminobenzophenone and identified by LC-MS/MS analysis. P5 interacted with CLIP-170 at its coiled-coil domain and changed it into an extended conformation. This increased CLIP-170 interaction with microtubules, dynactin subunit p150Glued, and LIS1; it also promoted CLIP-170-dependent microtubule polymerization. CLIP-170 was essential for P5 to promote microtubule abundance and zebrafish epiboly migration during embryogenesis; overexpression of the P5-binding region of CLIP-170 delayed this migration. P5 also sustained migration directionality of cultured mammalian cells. My results show that P5 regulates microtubule polymerization and cell migration via activating CLIP-170. Besides regulating microtubules, P5 also promoted resistance to the F-actin disrupting agent. P5 or CLIP-170 deficient embryos showed abnormal F-actin architectures and decreased endocytotic activity. P5 controlled interaction of CLIP-170 to the small GTPase Rho effector, mDia1. It suggests that P5 and CLIP-170 stabilize F-actin via mDia1. Together, P5 and CLIP-170 promote zebrafish embryonic movement by controlling both microtubule and F-actin.