Biophysical Society Thematic Meeting

New Biological Frontiers Illuminated by Molecular Sensors and Actuators

Poster Abstracts

25-POS

Board 25

Rapidly Rewriting Tubulin Codes inside Primary Cilia

Emily Su

1,2

, Takanari Inoue

2,1

Yu Chun Lin

3,2

Institute of Molecular Medicine, Naitonal Tsing Hua Univesity, Hsinchu City,

Taiwan.

Department of Biomedical Engineering, School of Medicine, Johns Hopkins University,

Baltimore, MD, USA,

Department of Cell Biology, School of Medicine, Johns Hopkins

University, Baltimore, MD, USA,

Primary cilium is a microtubule-based protrusion on the apical surface of almost every cell type

in our body, while functions as a sensory organelle that transduces extracellular cues to specific

intracellular functions. Dysfunctions of primary cilia consequently lead to a variety of human

diseases known as ciliopathies. Primary cilium is composed of a microtubule buddle called

axoneme that gives support to the structure and provides a track for cilia motors-dependent

movement. Axonemal tubulins undergo various post-translational modifications (PTMs) which

are tightly regulated by specific modifying enzymes. Although axonemal PTMs has been known

for several decades, deciphering how they regulate the structure and function of primary cilium

is still largely unchartered mainly due to a lack of techniques to locally manipulate axonemal

PTMs without affecting microtubule PTMs in the cell body. To overcome this long-standing

challenge, we have recently developed a “chemically inducible diffusion trap” (CIDT) technique

that allows us to translocate protein of interests (POIs) into primary cilia for manipulation of

ciliary composition or signaling locally on a second timescale. With this technique, we

translocated PTMs modifying enzymes specifically to axoneme for local perturbation of tubulin

PTMs in cilia. Accumulation of one deglutamylase, cytoplasmic carboxypeptidase 5 (CCP5), to

axoneme by our CIDT system can efficiently deglutamylate axonemal PTMs in cilia. This novel

approach enables us to evaluate the specific roles of axonemal PTMs in the structural integrity

and function of primary cilia and to understand how cilium gets organized and regulates itself by

axonemal PTMs.