Deficiency in the endocytic adaptor proteins PHETA1/2 impairs renal and craniofacial development

Kristin M. Ates, Tong Wang, Trevor Moreland, Rajalakshmi Veeranan-Karmegam, Manxiu Ma, Chelsi Jeter, Priya Anand, Wolfgang Wenzel, Hyung Goo Kim, Lynne A. Wolfe, Joshi Stephen, David R. Adams, Thomas Markello, Cynthia J. Tifft, Robert Settlage, William A. Gahl, Graydon B. Gonsalvez, May Christine Malicdan, Heather Flanagan-Steet, Y. Albert Pan

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


A critical barrier in the treatment of endosomal and lysosomal diseases is the lack of understanding of the in vivo functions of the putative causative genes. We addressed this by investigating a key pair of endocytic adaptor proteins, PH domain-containing endocytic trafficking adaptor 1 and 2 (PHETA1/2; also known as FAM109A/B, Ses1/2, IPIP27A/B), which interact with the protein product of OCRL, the causative gene for Lowe syndrome. Here, we conducted the first study of PHETA1/2 in vivo, utilizing the zebrafish system. We found that impairment of both zebrafish orthologs, pheta1 and pheta2, disrupted endocytosis and ciliogenesis in renal tissues. In addition, pheta1/2 mutant animals exhibited reduced jaw size and delayed chondrocyte differentiation, indicating a role in craniofacial development. Deficiency of pheta1/2 resulted in dysregulation of cathepsin K, which led to an increased abundance of type II collagen in craniofacial cartilages, a marker of immature cartilage extracellular matrix. Cathepsin K inhibition rescued the craniofacial phenotypes in the pheta1/2 double mutants. The abnormal renal and craniofacial phenotypes in the pheta1/2 mutant animals were consistent with the clinical presentation of a patient with a de novo arginine (R) to cysteine (C) variant (R6C) of PHETA1. Expressing the patient-specific variant in zebrafish exacerbated craniofacial deficits, suggesting that the R6C allele acts in a dominant-negative manner. Together, these results provide insights into the in vivo roles of PHETA1/2 and suggest that the R6C variant is contributory to the pathogenesis of disease in the patient.

Original languageEnglish (US)
Article numberdmm041913
JournalDMM Disease Models and Mechanisms
Issue number5
StatePublished - May 2020


  • Endocytosis
  • IPIP27A
  • OCRL
  • PHETA1
  • Undiagnosed disease

ASJC Scopus subject areas

  • Neuroscience (miscellaneous)
  • Medicine (miscellaneous)
  • Immunology and Microbiology (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)


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