Publication Date

2019

Document Type

Honors Project

Degree Name

Bachelor of Arts

Department

Biochemistry

Advisors

Nathan Derr

Keywords

Dynein, Cytoplasmic dynein, Molecular motor, Microtubule binding domain

Abstract

Dynein is a superfamily of minus-end directed, microtubule associated, cytoskeletal motor proteins (Vale, 2003). Cytoplasmic dynein often works in teams to facilitate the transport of essential cargo ranging from proteins to organelles (Roberts et al., 2013). The structure of cytoplasmic dynein is highly conserved across species (Redwine et al., 2012). Despite this highly conserved structure, the function of cytoplasmic dynein (characterized by processivity and velocity) varies widely across species (Jha & Surrey, 2015). This variability coupled with the high degree of conservation implies that a small number of amino acids regulate the function of cytoplasmic dynein. Redwine et al. identified key amino acids involved in mediating the interaction between the microtubule binding domain (MTBD) of dynein and the microtubule. Of particular interest is the residue at position 3337, which is the only residue that forms a microtubule-MTBD salt bridge which is not conserved between fungal and mammalian dynein. In order to investigate the role of the overall MTBD, and in particular the amino acid at position 3337, we engineered several mutant dynein chimeras with altered MTBDs. The function of these chimeric motors was quantified using total internal reflection fluorescence (TIRF) microscopy. Our results confirm that the structural elements of the MTBD, especially residues capable of forming microtubule-MTBD salt bridges such as Arg3337, modulate dynein processivity and velocity. Our results indicate that differences between the structure of the S. cerevisiae and H. sapiens dynein MTBD help explain the observed differences in function between S. cerevisiae and H. sapiens dynein.

Rights

©2019 Sarah Jane Flaherty. Access limited to the Smith College community and other researchers while on campus. Smith College community members also may access from off-campus using a Smith College log-in. Other off-campus researchers may request a copy through Interlibrary Loan for personal use.

Language

English

Comments

81 pages : color illustrations. Includes bibliographical references (pages 78-81)

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