Luis Gonzalez, Summer 2014, Blog Post 1

Hello everyone this is Luis Gonzalez a rising senior studying Biochemistry. I am currently funded through the HHMI EXROP program and I had the great opportunity to conduct my research at Stanford University and through their on local summer program SSRP. SSRP has great community of students and we have the privileged to be housed at Kairos, which houses all 33 students of our cohort.

Although it can get rowdy in afternoon, everyone single individual of the cohort is dedicated to his or her own respective research project. As for me I have the opportunity to work with Dr. Tim Stearns who is part of the departments of biology and genetics. The Stearns lab, which is found in Lorry Lokey shown below, focuses on understanding how the centrosome and primary cilium control cell function and influence development, and how defects in these structures cause a remarkable range of human disease, ranging from cancer, polycystic kidney disease, and obesity, to neurocognitive defects including mental retardation, schizophrenia, and dyslexia.

My specific project for the summer is studying microtubule nucleation and specifically to identify the proteins necessary for this event to occur. So a little background on the topic, microtubules are dynamic tubular structures composed of a/b-tubulin heterodimers, which are constantly undergoing periods of polymerization and depolymerization in order to alter their length in order to achieve their various roles. Microtubules play essential roles by providing structural integrity, transportation of vesicles and proteins, and most importantly the formation of the mitotic spindle, which is essential for the proper segregation of sister chromatids during the cell cycle. The organelle responsible for the formation of the mitotic spindle in eukaryotic mammalian cells is known as the centrosome, which is composed of a pair of centrioles, which are encompassed by pericentriolar material (PCM). The surface of the PCM is coated by ring complexes known as the g-tubulin ring complex (gTuRC), which based on structural studies of microtubules and the gTuRC have proposed microtubule nucleation to occur by a direct interaction of g-tubulin and a-tubulin. However the interaction between g-tubulin and a-tubulin has never been experimentally confirmed. Therefore the objective of my study is to definitively show that g-tubulin and a-tubulin interact and additionally to identify the residues involved in this interaction.

For my experiments, we decided to use Saccharomyces cerevisiae, which are grown in tubes shown above, as a model organism to conduct our studies due to the fact that all our genes of interest are conserved across all eukaryotic species. I made use of a technique known as the yeast two-hybrid system followed up by a b-galactosidase assay to quantify the strength of interaction between our proteins of interest, a-tubulin and g-tubulin.

Before I let you go I wanted to share a few images of the Stanford campus because it is a beautiful campus and bike friendly.