PARENT SESSION
PLATFORM SESSION 10: MATERNAL-FETAL ADAPTIONS TO PREGNANCY
Chair: Spencer, Thomas¹, ¹
Co-chair: Vonnahme, Kimberly¹, ¹
Harborside E
2:00 PM-4:00 PM

(223) MULTIPLE TRP ISOFORMS IMPLICATED IN CAPACITATIVE CALCIUM ENTRY ARE EXPRESSED IN HUMAN PREGNANT MYOMETRIUM AND MYOMETRIAL CELLS.

Yang, Ming¹, Gupta, Anupma¹, Shlykov, Sergiy¹, Corrigan, Rebecca¹, Tsujimoto, Susan¹, Sanborn, Barbara¹, ¹ Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, TX

ABSTRACT- Capacitative Ca²⁺ entry plays a role in increasing intracellular free Ca²⁺ in human myometrium. Capacitative Ca²⁺ entry was demonstrated in single PHM1-41 myometrial cells in response to thapsigargin and oxytocin. Members of the Trp protein family have been implicated in capacitative Ca²⁺ entry in a number of tissues. Pregnant human myometrium and the human myometrial cell line PHM1-41 express mRNA for hTrp1, hTrp3, hTrp4, hTrp6 and hTrp7. hTrp1 and hTrp4a and b splice variants mRNA were expressed in both tissue and cells. In addition, novel splice variants for hTrp1 and hTrp3 were discovered. hTrp11 (121bp) and hTrp12 (55bp) contain insertions between previously described exons 9 and 10 that would alter reading frame and produce Trp proteins truncated in the membrane spanning region if expressed. The hTrp3 (hTrp3) variant introduces sequence between exons 8 and 9 that would insert 16 amino acids in the C-terminal region of the protein upstream of the calmodulin and IP3 receptor interaction domain. hTrp1, hTrp3 and hTrp4 proteins were detected in PHM1-41 membranes. These data are consistent with the presence of proteins that could form putative capacitative Ca²⁺ channels in human myometrium. Control of the activity of these channels may be important for the control of uterine contractile activity. Supported by HD09618, HD38970 and Lalor Foundation Fellowships (M.Y. and A.G.).

KEY WORDS: capacitative calcium entry , Trp proteins, myometrium