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Ricardo E. Dolmetsch (Ph.D ) is an assistant professor of Neurobiology and Molecular Pharmacology at Stanford University of Medicine in California, USA. His early work in the study of calcium channels and technology research led to increased knowledge in the field of intracellular cell signaling pathways. His contributions to science have earned him a multitude of distinguished awards including: the McKnight Technological Innovations in Neuroscience Award (2004-2006), the Society for Neuroscience Young Investigator Award (2007), the Axelrod Lecturer Society for Neuroscience Award, and the National Institutes of Health Pioneer Award (2008-2013). Current fields of interest include the underlying neurobiology of autism and other neuro-developmental disorders, with a focus on how electrical activity and calcium signals control brain development and how it is altered in children with autism spectrum disorders. Other goals include the development of tools for the study and repair of the brain.

Early Life
Ricardo Dolmetsch was born in Cali, Columbia, and immigrated to the US when he was 17. His father is the former director of the local symphony orchestra in Cali, and is currently a freelance photographer. His mother is a feminist politician, and candidate for elected office. Dolmetsch started his work in experimental Biology at a young age, when he used his father’s stereo to amplify the stretch receptor potentials of a cockroach thigh muscle. Dolmetsch graduated top of his class in high school and was an accomplished athlete. He is a former Colombian national long jump champion and represented Colombia in the Pan-American and Junior World Championships in the long jump event.

Education
Dolmetsch graduated with honours from Brown University, where he received a B.Sc. in neuroscience. During his time at Brown he worked as a writer and photographer for the Brown Daily Herald, and as a lab assistant where he aided in the characterization of regenerating axons. Apart from Neuroscience Dolmetsch studied Computer Science, which would become useful in his later experimental work. Occasionally he would work as an orderly at a Colombian hospital, and as an intern for the World Health Organization.

After leaving Brown, Dolmetsch went on to do graduate work at Stanford University, where he worked under Rich Lewis. He received a Ph.D. in neuroscience from Stanford in 1997. During his graduate studies he wrote the software responsible for controlling a patch clamp experiment, and developed a calcium clamp to study how oscillations in calcium affect gene expression. While obtaining his Ph.D. he gained teaching experience from tutoring Latino students in East San Jose, and as a teaching assistant in the Stanford Medical School Neurobiology class. During the summer, Dolmetsch worked as a teaching assistant for the imaging course at Cold Spring Harbor.

Dolmetsch married Asha Nigh in 1999, and they have two sons: Max Balam Dolmetsch, and Rio Santiago Dolmetsch. In 1997 he began work as a post-doctoral fellow under Mike Greenberg, at Harvard University. While at Harvard, Dolmetsch studied molecular biology and biochemistry. He also became interested in marathon running, and ran the Boston Marathon, finishing in three hours and seven minutes. After completing his education in 2003, Dolmetsch became an assistant professor in the Department of Molecular Pharmacology at the Stanford University of Medicine. In 2005 he became an assistant Professor in the department of Neurobiology, a position he still currently holds.

Development and calcium signalling research
The Dolmetsch lab has been committed in the recent past to investigating how calcium channels activate signalling cascades that control gene expression, neuronal differentiation, mitigation and survival in relation to the development of autism. In 2001 Dolmetsch and associates concluded that the regulation of L-type calcium channels in neurons and the proteins that interact with them at the cell surface, such as calmodulin(CaM), are critical first steps in the regulation of CREB, CRE, the MAPKinase pathway, and ERK. These proteins are associated with the signalling cascade from the cell surface to the nucleus for the regulation of transcription factors, which mediate cell fate determination and cellular differentiation.

Calcium Channels
In 2001, functional knock-in techniques were developed in Dolmetsch’s lab in order to be able to investigate features of voltage gated calcium channels. Calcium channels are necessary for the regulation of biochemical and physical properties of neurons and muscle cells. Using knock-in techniques to focus on features that couple the L-type voltage gated calcium channels (LTC) to signalling pathways that regulate gene expression showed that the isoleucine-glutamine (IQ) motif, which binds Ca2+-calmodulin (CaM), is essential for conveying the calcium signal to the nucleus. Activation of the Ras/mitogen-activated protein kinase (MAPK) pathway relies on the Ca2+-CaM binding to the LTC. CaM functions as a sensor for calcium at the mouth of the LTC that activates the MAPK pathways. The MAPK conveys local signals from the LTC to the nucleus and leads to the stimulation of genes necessary for neuronal survival and plasticity. Later in 2006, it was found that in CaV1.2, a type of LTC, the C-terminal fragment of the channel translocates to the nucleus and regulates transcription. This calcium channel associated transcription regulator (CCAT) binds to a nuclear protein, which then associates with an endogenous promoter and regulates the expression of a wide range of endogenous genes that are important for neuronal signalling. This suggests that voltage-gated calcium channels can directly activate transcription without an intermediate signalling pathway, and provides a mechanism linking voltage-gated channels to the function and differentiation of excitable cells. LTC’s can also contribute to cellular dysfunction or death under pathological conditions. Activation of N-Methyl-D-aspartic acid receptors causes internalization and degradation of CaV1.2 channels reducing both Ca2+ entry into the cell and the Ca2+ toxicity. Knockdown of PIKfyve, a lipid kinase, prevents CaV1.2 degradation and increases neuronal susceptibility to excitotoxicity. This shows a new mechanism by which neurons are protected from excitotoxicity. Other calcium channels Dolmetsch has worked on include store-operated calcium channels,(SOC’s), which are critically important for several biological processes, including activation of the immune system. The SOC channels are composed of Orai, which is an ion channel in the plasma membrane of cells, Stim, which is an endoplasmic reticulum (ER) protein that contains a calcium-binding domain in the lumen of the ER, and a cytoplasmic domain. Using a variety of approaches he found that Stim activates Orai by binding directly to it.

Autism Research
When his son was diagnosed with autism at the age of four, Dolmetsch decided to switch the main focus of his lab from a more basic science focus on calcium channel to the study of the development of autism. The current goal of the lab is to understand the molecular and cellular basis of autism spectrum disorders and to identify molecular targets for new drug development. Dolmetsch’s previous research on LTCs, specifically the Cav1.2, has been implicated in the development of certain types of autism spectrum disorder. Point mutations in the gene CACNA1C (which encodes the CaV1.2 channel) causes Timothy’s syndrome, a rare multi-system disorder that is characterized by cardiac abnormalities and a high prevalence of autism. CaV1.2 are expressed mostly in neuronal dendrites and cell bodies and are involved in the regulation of calcium related signaling cascades. It is also important for neuronal survival and dentritic arborization. Timothy’s syndrome is linked to mutations in the CaV1.2 channel that prevent its voltage dependent inactivation, allowing for increased opening periods and prolonged calcium influx. Although these mutations may be linked to the development of autism, little is known about their biological consequences and no causal conclusions can be drawn.

Currently the Dolmetsch lab is focusing on the use of pleuripotent stem cells to further understand the development of autism. Since pleuripotent stem cell have the ability to develop into any cell type, the lab is using skin cells obtained from autistic children to develop neurons, and some cardiac cells, to better characterize possible mutations and to help identify new drug targets. In order to accomplish this, researchers at the Dolmetsch lab are currently recruiting autism spectrum disorder patients and asking them for a punch biopsy to obtain a skin sample, along with check swabs and blood samples. The tissues are then used to create the pleuripotent stem cells, which then become neural tubes and are then manipulated into a neurosphere that resembles a functioning cortex. Only the cortex is developed, as this is the region most likely to be affected in an autism spectrum disorder. With regards to the validation of pleuripotent stem cells as a model of autism spectrum disorders, mutations seen in these cells have also been seen in mouse models of these disorders. This research is relatively new and only a few participants have been studied, however Dr. Dolmetsch has been able to a identify a class of participants with mutations that cause overproduction of norepinephrine and suggest norepinephrine antagonists as a possible treatment. This research is still in its infancy and further studies are necessary to fully validate this model, especially with regards to demonstrating drug treatments that work on the cell models have beneficial behavioural outcomes in actual patients.

New Technologies
During the course of his career, Dr. Dolmetsch and the members of his lab developed a number of new technologies useful in research into cell biology. The foremost among them is Light-Activated Dimerisation.

Light-Activated Dimerisation
In 2009, the Dolmetsch lab devised a means to construct proteins that would bind each other when exposed to 450nm (blue) light. This technology was called light-activated dimerisation (LAD) and permitted artificial protein dimerisation that could be easily controlled both spatially and temporally. This system is based on the FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1) and GIGANTEA (GI) proteins that control flowering in Arabidopsis thaliana. After adding a G128D FKF1 mutant as a domain to one target protein and GI to the other target protein, the two targets will bind (dimerise) when exposed to 450nm illumination. The G128D mutation is necessary to eliminate background binding in darkness. The FKF1 and GI domains will dissociate approximately 90 minutes after the illumination is turned off, making the resulting dimerisation non-permanent. This technique can be used to induce the dimerisation of intracellular and transmembrane receptors, providing fine control over when cells start detecting signalling molecules. The Dolmetsch lab also showed how this technique could be applied to control gene transcription directly by fusing FKF1 to FV16 and GI to Gal4. When bound together, Gal4 and FV16 produce a very potent transcription activator in mammalian] cells. So when blue light induces binding of the GI and FKF1 domains, the Gal4-FV16 complex forms and, in turn, induces [[transcription.