Charcot-Marie-Tooth-related Gene GDAP1 Complements Cell Cycle Delay at G2/M Phase in Saccharomyces cerevisiae fis1 Gene-defective Cells

Abstract

Mutations in the GDAP1 gene are responsible of the CharcotMarie-Tooth CMT4A, ARCMT2K, and CMT2K variants. GDAP1 is a mitochondrial outer membrane protein that has been related to the fission pathway of the mitochondrial network dynamics. As mitochondrial dynamics is a conserved process, we reasoned that expressing GDAP1 in Saccharomyces cerevisiae strains defective for genes involved in mitochondrial fission or fusion could increase our knowledge of GDAP1 function. We discovered a consistent relation between Fis1p and the cell cycle because fis1⌬ cells showed G 2 /M delay during cell cycle progression. The fis1⌬ phenotype, which includes cell cycle delay, was fully rescued by GDAP1. By contrast, clinical missense mutations rescued the fis1⌬ phenotype except for the cell cycle delay. In addition, both Fis1p and human GDAP1 interacted with ␤-tubulins Tub2p and TUBB, respectively. A defect in the fis1 gene may induce abnormal location of mitochondria during budding mitosis, causing the cell cycle delay at G 2 /M due to its anomalous interaction with microtubules from the mitotic spindle. In the case of neurons harboring defects in GDAP1, the interaction between mitochondria and the microtubule cytoskeleton would be altered, which might affect mitochondrial axonal transport and movement within the cell and may explain the pathophysiology of the GDAP1-related Charcot-Marie-Tooth disease.

Structural and functional divergence of GDAP1 from the glutathione S‐transferase superfamily

“…Crystallization of GDAP1 was facilitated by the replacement of the α‐loop (amino acids 145‐200) with a tripeptide GTG‐linker. Limited sequence homology between this region and GSTs had made it difficult to predict a priori whether the α‐loop was an independent domain in between G‐ and H‐sites 16,20,52 or whether it was instead an integral part of the canonical fold. While our structural data do not inform directly on the structure of the α‐loop, helices α4 and α5 in GDAP1 are positioned in a manner similar to most other GSTs, indicating that the α‐loop is an insertion within the H‐site.…”

Mitochondrial dynamics in neurodegeneration

“…GDAP1 is a mitochondrial outer membrane protein that has been implicated in mitochondrial fission, although the exact role of GDAP1 in organelle division is less understood than that of Drp1 [72, 73]. Recent studies have reported two cases in which CMT patients carry mutations in both Mfn2 and GDAP1 [74, 75].…”

Mitochondria in lung diseases

“…At M phase exit, fusion resumes [27,59–62]. Furthermore, proteins involved in mitochondrial dynamics, such as Fis1 and GDAP1, have been reported to interact with microtubules, which are integral members in cell division [63]. These fission/fusion processes during the cell cycle become relevant to the disease state when factors such as inflammatory or infectious mediators, ROS/RNS and environmental stimuli alter these processes (e.g.…”