Higher Expression of TRPM7 Channels in Murine Mature B Lymphocytes than Immature Cells

• 영문명: Higher Expression of TRPM7 Channels in Murine Mature B Lymphocytes than Immature Cells
• 발행기관: 대한생리학회-대한약리학회
• 저자명: Jin Kyoung Kim Jae Hong Ko Joo Hyun Nam Ji-Eun Woo Kyeong Min Min Yung E Earm Sung Joon Kim
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제9권 제2호, 69~76쪽, 전체 8쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 2005.01.01

영문 초록

TRPM7, a cation channel protein permeable to various metal ions such as Mg^2⁢, is ubiquitously expressed in variety of cells including lymphocytes. The activity of TRPM7 is tightly regulated by intracellular Mg^2⁢, thus named Mg^2⁢-inhibited cation (MIC) current, and its expression is known to be critical for the viability and proliferation of B lymphocytes. In this study, the level of MIC current was compared between immature (WEHI-231) and mature (Bal-17) B lymphocytes. In both cell types, an intracellular dialysis with Mg^2⁢-free solution (140 mM CsCl) induced an outwardly-rectifying MIC current. The peak amplitude of MIC current and the permeability to divalent cation (Mn^2⁢) were several fold higher in Bal-17 than WEHI-231. Also, the level of mRNAs for TRPM7, a molecular correspondence of the MIC channel, was significantly higher in Bal-17 cells. The amplitude of MIC was further increased, and the relation between current and voltage became linear under divalent cation-free conditions, demonstrating typical properties of the TRPM7. The stimulation of B cell receptors (BCR) by ligation with antibodies did not change the amplitude of MIC current. Also, increase of extracellular [Mg^2⁢]_c to enhance the Mg^2⁢ influx did not affect the BCR ligation-induced death of WEHI-231 cells. Although the level of TRPM7 was not directly related with the cell death of immature B cells, the remarkable difference of TRPM7 might indicate a fundamental change in the permeability to divalent cations during the development of B cells.

키워드

B lymphocyte TRPM7 Nonselective cation channel Cell death Bal-17 WEHI-231