Functional and structural organization of lysosomal membrane proteins Bridget Moira McVeigh

Format:

Book

Thesis/Dissertation

Author/Creator:

McVeigh, Bridget Moira, author.

Contributor:

University of Pennsylvania. Pharmacology., degree granting institution.

Language:

English

Subjects (All):

Cellular biology.

Pharmacology.

Molecular biology.

Immunology.

0379.

0982.

0419.

0307.

Local Subjects:

Cellular biology.

Pharmacology.

Molecular biology.

Immunology.

0379.

0982.

0419.

0307.

Genre:

Academic theses

Physical Description:

1 online resource (120 pages)

Contained In:

Dissertations Abstracts International 87-12B

Place of Publication:

Ann Arbor : ProQuest Dissertations and Theses, 2026

Language Note:

English

Summary:

Lysosomes are central regulatory organelles that maintain cellular homeostasis by serving as micronutrient reservoirs and membrane platforms for essential signaling pathways. Their dysfunction underlies lysosomal storage disorders (LSDs), neurodegenerative disorders, lung disease, autoimmunity, and cancer. Despite their importance, how lysosomal membrane proteins are functionally and structurally organized to coordinate signaling remains poorly understood. Transient receptor potential mucolipin 1 (TRPML1) is a lysosomal calcium (Ca2+) permeable ion channel essential for lysosomal homeostasis, membrane trafficking, and nutrient signaling. Mutations in the TRPML1 channel cause Mucolipidosis type IV (MLIV) disease, a rare autosomal recessive LSD with profound neurodevelopment impairments, and TRPML1 dysfunction has been implicated in neurodegenerative disease, metabolic disorders, and cancer. Despite its central role in lysosomal function and disease, the membrane assemblies that coordinate TRPML1 activity remain poorly defined. In this work, quantitative interaction proteomics revealed that TRPML1 is embedded within a transporter-enriched proteomic network. We identify the lysosomal amino acid transporter solute carrier family 38 member 9 (SLC38A9) as a direct TRPML1-interacting partner. Functional experiments demonstrate that depletion of SLC38A9 attenuates TRPML1-mediated Ca2+ release and super-resolution DNA Point Accumulation in Nanoscale Topography (DNA-PAINT) imaging further revealed that SLC38A9 regulates the nanoscale organization of TRPML1 at the lysosomal membrane, as depletion of SLC38A9 promotes the formation of larger, less-dense TRPML1 nanoclusters. Structural modeling and molecular dynamics simulations identified a candidate interaction interface adjacent to the phosphoinositide regulatory region of TRPML1, providing a potential mechanistic basis for channel-transporter coupling. Together, these findings define a previously unrecognized lysosomal channel-transporter assembly, suggesting a link between calcium signaling with amino acid sensing at the lysosomal membrane level. To place lysosomal membrane protein interactions within their native structural context, we further developed a robust cryogenic electron tomography (cryoET) workflow for visualizing lysosomal membrane proteins in intact organelles. Using immunopurification strategies independently targeting two lysosomal membrane proteins, TRPML1 and transmembrane protein 192 (TMEM192), we isolated intact endolysosomal organelles suitable for structural analysis. Sub-tomogram averaging enabled structural refinement of key membrane and membrane-associated complexes, including vacuolar-type ATPase (V-ATPase), Flotillin, and Clathrin, directly within native lysosomal membranes. These studies establish a structural foundation for investigating lysosomal membrane organization. Together, this dissertation provides a functional and structural framework for how lysosomal membrane proteins coordinate signaling and introduces a new approach for visualizing lysosomal membrane organization, establishing a platform to study how disruptions in lysosomal signaling contribute to human disease

Notes:

Source: Dissertations Abstracts International, Volume: 87-12, Section: B.

Advisors: Moiseenkova-Bell, Vera Y.; Mitchell, Claire H. Committee members: Chang, Yi-Wei; Marks, Michael S.; Ren, Deijan

Ph.D. University of Pennsylvania 2026

Vendor supplied data

Local Notes:

School code: 0175

ISBN:

9798247973607

Access Restriction:

Restricted for use by site license