Diamond controls epithelial polarity through the dynactin-dynein complex

Area of Science:

• Cell Biology
• Developmental Biology
• Molecular Biology

Background:

• Epithelial polarity is crucial for tissue function, cancer, and metastasis.
• The Crumbs (Crb) protein is a key regulator of epithelial polarity, with both protein and transcripts localized apically.
• Mechanisms for apical targeting of Crb remain incompletely understood.

Purpose of the Study:

• To investigate the role of Diamond (Dind) in the apical localization of Crb protein and transcripts.
• To elucidate the molecular pathway involved in Crb apical targeting.

Main Methods:

• Utilized Drosophila ovarian follicular epithelia as a model system.
• Employed co-immunoprecipitation followed by mass spectrometry (co-IP-MS) to identify Dind-interacting proteins.
• Performed genetic depletion studies to assess the function of Dind and dynactin.

Main Results:

• Loss of Dind in follicular cells (FCs) resulted in loss of epithelial polarity and apical Crb protein.
• Dind associates with components of the dynactin-dynein complex.
• Dind stabilizes dynactin, and dynactin depletion phenocopies dind defects.
• Dind and dynactin are required for apical localization of both Crb protein and transcripts.

Conclusions:

• Dind functions via dynactin/dynein-mediated transport to deliver Crb protein and transcripts to the apical domain.
• This pathway is critical for establishing and maintaining epithelial apico-basal (A/B) polarity.