Rosa Puertollano graduated from the Universidad Autonoma de Madrid with a B.S. in biology and biochemistry and a M.S. in molecular genetics. She earned her Ph.D. in molecular biology and biochemistry from Consejo Superior de Investigaciones Cientificas and did her postdoctoral training from 1999 to 2004 in the Cell Biology and Metabolism Branch of the National Institute of Child Health and Human Development at the NIH. From 2001 to 2004 she was an NIH visiting fellow and subsequently became a tenure-track Investigator at the NHLBI. Dr. Puertollano has published over 50 research articles, reviews, and book chapters. She is a member of the editorial board of the journals Traffic and ISRN Cell Biology and a reviewer for numerous other journals. She is a member of the American Society for Cell Biology, the NIH Protein Trafficking Interest Group, and the Faculty of 1000.
The selective recycling of lipids and proteins is critical to healthy cellular function. Many genes associated with human diseases encode components of the cellular machinery that sorts lipids and proteins for selective trafficking along endocytotic pathways leading to lysosomal degradation. Dr. Puertollano seeks to understand precisely how defects in intracellular trafficking—specifically, in endosomal/lysosomal pathways—contribute to human diseases.
The current focus of her work is the function of mucolipins, a novel family of ion channels that belongs to the superfamily of transient receptor potential (TRP) channels. In mammals, the mucolipin family includes three members, mucolipin-1, -2, and -3 (MCOLN1-3), which share approximately 75% amino acid similarity. Loss-of-function mutations of human MCOLN1 result in mucolipidosis type IV (MLIV), a lysosomal storage disorder characterized by severe neurological and ophthalmologic abnormalities. Meanwhile, gain-of-function mutations in mouse MCOLN3 cause the varitint-waddler phenotype that shows pigmentation and hearing defects. Thus, MCOLNs play an important role in cellular function yet their properties and functions are not completely understood.
By using a combination of biochemistry, confocal, and electronic microscopy, Dr. Puertollano has found that MCOLNs are located to endosomes and lysosomes, where they appear to regulate changes in the luminal ion composition of endosomal organelles. Well-regulated storage and release of ions, like calcium, is clearly important for membrane trafficking and signaling, but little is known about the regulation of ion concentration within endosomal organelles. To gain better understanding, Dr. Puertollano has extended her in vitro studies of MCOLNs to animal models using genetic approaches in zebrafish and mice. Her goal is to uncover pathological cascades beginning with alterations in basic homeostatic mechanisms of intracellular compartments that may be common to many diseases.
Finally, Dr. Puertollano has recently started a new project elucidating the molecular mechanisms that regulate the localization and activity of TFEB, a member of the basic helix-loop-helix leucine-zipper family of transcription factors that control expression of autophagic and lysosomal genes. TFEB regulates lysosomal exocytosis, increasing the presence of lysosomes near the cell membrane and promoting their fusion with the membrane. This transcription factor was also shown to interact with the energy-sensing mammalian target of rapamycin (MTOR) protein kinase complex, and Dr. Puertollano is exploring the role of lysosomes as signaling centers that synchronize environmental cues with gene expression, energy production, and cellular homeostasis.