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JHA, ANUPMA (2011) CLATHRIN-MEDIATED ENDOCYTOSIS OF YOLK PROTEIN IN THE DROSOPHILA OOCYTE. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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The developing egg chamber of Drosophila accumulates yolk protein to utilize during embryonic development. Egg chamber development is divided in 14 different stages, yolk
protein endocytosis occurs between stages 8-11. Yolk protein is present in hemolymph, and the ovaries are bathed in hemolymph. Yolk protein forms a complex with Yolkless
for endocytosis in oocyte. Yolkless is an LDL receptor superfamily member, and its cytosolic tail contains the signal for internalization by clathrin-mediated endocytosis. The Yolkless cytosolic tail harbors an typical FxNPxA sequence instead of the commonly found tyrosine-based sorting signal FxNPxY. The tyrosine-based sorting signals interact with PTB domain-containing proteins. In the present study, I show that PTB domaincontaining phagocytic protein Ced-6 is expressed in the cortical region of oocyte of the egg chamber. Ced-6 harbors all the biochemical properties of clathrin-associated sorting proteins. Ced-6 can physically interact with clathrin, AP-2 and phosphoinositide(4,5)P2.
The Ced-6 PTB domain interacts with the cytosolic tail of Yolkless and clusters Yolkless into clathrin-coated pit. This clustering leads to internalization of Yolkless by clathrinmediated endocytosis. In conjunction with the FxNPxA signal, Yolkless cytosolic tail contains a functional, although atypical, dileucine signal. This atypical dileucine signal can physically interact with AP-2. This interaction leads to the clathrin-mediated
endocytosis of Yolkless. Clathrin adaptor AP-2 and Ced-6 function redundantly in yolk protein uptake, as Ced-6-null flies accumulate yolk protein. Results from this study led to a model where both AP-2 and Ced-6 interact with Yolkless independently to ensure its internalization. Interaction of Ced-6 with clathrin and AP-2 leads to effective clustering
of Yolkless for internalization by clathrin-mediated endocytosis.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
JHA, ANUPMAanj14@pitt.eduANJ14
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairApodaca, Gerardgla6@pitt.eduGLA6
Thesis AdvisorTraub, Lintontraub+@pitt.eduTRAUB
Committee MemberAridor, Meiraridor@pitt.eduARIDOR
Committee MemberHong, Yangyhong@pitt.eduYHONG
Committee MemberLee,
Date: 2011
Date Type: Publication
Defense Date: 8 December 2011
Approval Date: 20 December 2011
Submission Date: 18 December 2011
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 163
Institution: University of Pittsburgh
Schools and Programs: School of Medicine > Cell Biology and Molecular Physiology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Drosophila, Endocytosis, Oocyte, clathrin, Yolkless, Ced-6, AP-2
Date Deposited: 20 Dec 2011 13:01
Last Modified: 15 Nov 2016 13:55


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