Cleavage of TRPM7 releases the kinase domain from the ion channel and regulates its participation in Fas-induced apoptosis.
Transient receptor potential melastatin-like 7 (TRPM7) is a channel protein that also contains a regulatory serine-threonine kinase domain. Here, we find that Trpm7-/- T cells are deficient in Fas-receptor-induced apoptosis and that TRPM7 channel activity participates in the apoptotic process and is regulated by caspase-dependent cleavage. This function of TRPM7 is dependent on its function as a channel, but not as a kinase. TRPM7 is cleaved by caspases at D1510, disassociating the carboxy-terminal kinase domain from the pore without disrupting the phosphotransferase activity of the released kinase but substantially increasing TRPM7 ion channel activity. Furthermore, we show that TRPM7 regulates endocytic compartmentalization of the Fas receptor after receptor stimulation, an important process for apoptotic signaling through Fas receptors. These findings raise the possibility that other members of the TRP channel superfamily are also regulated by caspase-mediated cleavage, with wide-ranging implications for cell death and differentiation.
Department of Cardiology, Howard Hughes Medical Institute, Manton Center for Orphan Disease, Children's Hospital Boston, and Department of Neurobiology, Harvard Medical School, Enders Building 1309, 320 Longwood Avenue, Boston, MA 02115, USA.
Bimal N
BN
Desai
Grigory
G
Krapivinsky
Betsy
B
Navarro
Luba
L
Krapivinsky
Brett C
BC
Carter
Sebastien
S
Febvay
Markus
M
Delling
Anirudh
A
Penumaka
I Scott
IS
Ramsey
Yunona
Y
Manasian
David E
DE
Clapham
D000818:Animals; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D004705:Endocytosis; D006801:Humans; D007473:Ion Channels / Q000378:metabolism; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D050053:TRPM Cation Channels / Q000378:metabolism*; D019014:fas Receptor / Q000378:metabolism*
C491901:FAS protein, human; C491899:Fas protein, mouse; D007473:Ion Channels; D050053:TRPM Cation Channels; D019014:fas Receptor; C421903:Trpm7 protein, mouse; D017346:Protein Serine-Threonine Kinases; C486583:TRPM7 protein, human; D020169:Caspases