THESIS
2017
xi, 53 pages : color illustrations ; 30 cm
Abstract
Delivery of different proteins to proper locations is important for them to exert specific function. Thereby, protein trafficking plays a critical role in maintaining the normal cellular morphology and function. This complicated process involves hundreds of signaling molecules and proteins. PICK1 (Protein interacting with C-kinase 1) is a peripheral membrane protein expressed widely in various tissues. As the only protein containing both a PDZ domain and a BAR domain, PICK1 mainly functions in protein transport. In pancreas, PICK1 interacts with ICA69 (Islet cell autoantigen 69kDa) to form a complex responsible for the biogenesis and maturation of insulin granules. In pituitary gland, these two proteins bind together as well and regulate the storage and secretion of growth hormone. PICK...[
Read more ]
Delivery of different proteins to proper locations is important for them to exert specific function. Thereby, protein trafficking plays a critical role in maintaining the normal cellular morphology and function. This complicated process involves hundreds of signaling molecules and proteins. PICK1 (Protein interacting with C-kinase 1) is a peripheral membrane protein expressed widely in various tissues. As the only protein containing both a PDZ domain and a BAR domain, PICK1 mainly functions in protein transport. In pancreas, PICK1 interacts with ICA69 (Islet cell autoantigen 69kDa) to form a complex responsible for the biogenesis and maturation of insulin granules. In pituitary gland, these two proteins bind together as well and regulate the storage and secretion of growth hormone. PICK1 is also involved in the formation of proacrosomal granules in testis and related to male infertility. However, currently only a few proteins have been identified as the binding partner of PICK1 responsible for protein trafficking and further investigation is required to fully elucidate the function of PICK1.
In this study, LDB3 (LIM Domain Binding 3) was identified as a new PICK1 interacting protein by IP-MS method. These two proteins could bind to each other in vitro. Their
interaction was further confirmed by in vivo co-immunoprecipitation experiment. Results of domain mapping assays showed that this interaction was dependent on the PDZ domain of PICK1 and the PDZ-binding motif at the C terminus of LDB3. Overexpressed in HEK293T cells, PICK1 and LDB3 co-localized together and formed unique vesicle-like structures.
Moreover, these vesicle-like structures relied on their molecular interaction. Mutations abolishing the interaction of LDB3 and PICK1 totally disrupted their co-localization. Our data demonstrated that LDB3 could interact with PICK1 endogenously and their association might function in protein trafficking.
Post a Comment