Activity of the calcium channel pore Cch1 is dependent on a modulatory region of the subunit Mid1 in Cryptococcus neoformans

Min Pyo Hong, Kiem Vu, Jennifer M. Bautos, Rick Tham, Mantana Jamklang, John P. Uhrig, Angela C Gelli

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Calcium (Ca2+)-mediated signaling events in fungal pathogens such as Cryptococcus neoformans are central to physiological processes, including those that mediate stress responses and promote virulence. The Cch1-Mid1 channel (CMC) represents the only high-affinity Ca2+ channel in the plasma membrane of fungal cells; consequently, cryptococci cannot survive in low-Ca2+ environments in the absence of CMC. Previous electrophysiological characterization revealed that Cch1, the predicted channel pore, and Mid1, a binding partner of Cch1, function as a store-operated Ca2+-selective channel gated by depletion of endoplasmic reticulum (ER) Ca2+ stores. Cryptococci lacking CMC did not survive ER stress, indicating its critical role in restoring Ca2+ homeostasis. Despite the requirement for Mid1 in promoting Ca2+ influx via Cch1, identification of the role of Mid1 remains elusive. Here we show that the C-terminal tail of Mid1 is a modulatory region that impinges on Cch1 channel activity directly and mediates the trafficking of Mid1 to the plasma membrane. This region consists of the last 24 residues of Mid1, and the functional expression of Mid1 in a human embryonic cell line (HEK293) and in C. neoformans is dependent on this domain. Substitutions of arginine (R619A) or cysteine (C621A) in the modulatory region failed to target Mid1 to the plasma membrane and prevented CMC activity. Interestingly, loss of a predicted protein kinase C (PKC)-phosphorylated serine residue (S605A) had no effect on Mid1 trafficking but did alter the kinetics of Cch1 channel activity. Thus, establishment of Ca2+ homeostasis in C. neoformans is dependent on a modulatory domain of Mid1.

Original languageEnglish (US)
Pages (from-to)142-150
Number of pages9
JournalEukaryotic Cell
Volume12
Issue number1
DOIs
StatePublished - Jan 2013

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Cryptococcus neoformans
Calcium Channels
Cryptococcus
Cell Membrane
Homeostasis
Physiological Phenomena
Endoplasmic Reticulum Stress
Endoplasmic Reticulum
Serine
Protein Kinase C
Cysteine
Virulence
Arginine
Tail
Calcium
Cell Line

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

Cite this

Activity of the calcium channel pore Cch1 is dependent on a modulatory region of the subunit Mid1 in Cryptococcus neoformans. / Hong, Min Pyo; Vu, Kiem; Bautos, Jennifer M.; Tham, Rick; Jamklang, Mantana; Uhrig, John P.; Gelli, Angela C.

In: Eukaryotic Cell, Vol. 12, No. 1, 01.2013, p. 142-150.

Research output: Contribution to journalArticle

Hong, Min Pyo ; Vu, Kiem ; Bautos, Jennifer M. ; Tham, Rick ; Jamklang, Mantana ; Uhrig, John P. ; Gelli, Angela C. / Activity of the calcium channel pore Cch1 is dependent on a modulatory region of the subunit Mid1 in Cryptococcus neoformans. In: Eukaryotic Cell. 2013 ; Vol. 12, No. 1. pp. 142-150.
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