PEREZ CORNEJO, GLORIA PATRICIA

RESEARCH

My work is focused on two topics: TMEM16A channels and P2X7 purinergic receptors.

TMEM16A channels

The calcium-activated chloride channels TMEM16A and TMEM16B play a role in numerous physiological processes such as: water and electrolyte secretion, sensory transduction, regulation of vascular tone, cardiac excitability and neuronal excitability. The genes ANO1 and ANO2 that code for these channels were identified in 2008. I am interested in learning about the activation and regulatory mechanisms that allow the TMEM16A channel to function in a cellular context. Thus far we have learned that TMEM16A displays complex chloride current kinetics since channel gating involves interactions between the intracellular calcium concentration, membrane depolarization, extracellular Cl−, permeant anions and binding of extracellular protons to glutamic acid 623 and intracellular protons to the calcium-pocket. In addition, cytosolic factors, cytoskeletal proteins, and membrane lipids modulate channel activity. For example, we found that cAMP down regulates CaCC through a dual mechanism involving PKA and CFTR; downregulating the expression of moesin in HEK-293 cells changes channel activity; PI(4,5)P2 is required for TMEM16A activity while cholesterol regulate channel function but is not essential. We also found that exogenous stearic, arachidonic, oleic, docosahexaenoic, and eicosapentaenoic fatty acids inhibit TMEM16A in a dose- and voltage-dependent manner.

P2X7 purinergic receptors

Purinergic receptors belong to the P2X receptor family composed of seven members that function as cationic channels when activated by extracellular ATP. These receptors are expressed in the central nervous system, immune system and other tissues. We have studied the crossregulation of P2X4 and P2X7 receptors. Until 2007 it was believed that P2X7 did not interact with other purinergic receptors. We showed that P2X4 and P2X7 interact with each other through protein-protein contacts. This interaction is relevant for the physiological function of mouse macrophages. Also, we have documented the importance of P2X7 in the phagocytosis of yeast and bacteria.

TEACHING

I devote some of my time to learn about the effectiveness of different teaching interventions to help my students learn more effectively. I am also interested in applying the Item Response Theory for item banking and test equating.