title: Newly identified motifs in Candida albicans Cdr1 protein nucleotide binding domains are pleiotropic drug resistance subfamily-specific and functionally asymmetric.
abstract: An analysis of Candida albicans ABC transporters identified conserved related α-helical sequence motifs immediately C-terminal of each Walker A sequence. Despite the occurrence of these motifs in ABC subfamilies of other yeasts and higher eukaryotes, their roles in protein function remained unexplored. In this study we have examined the functional significance of these motifs in the C. albicans PDR transporter Cdr1p. The motifs present in NBD1 and NBD2 were subjected to alanine scanning mutagenesis, deletion, or replacement of an entire motif. Systematic replacement of individual motif residues with alanine did not affect the function of Cdr1p but deletion of the M1-motif in NBD1 (M1-Del) resulted in Cdr1p being trapped within the endoplasmic reticulum. In contrast, deletion of the M2-motif in NBD2 (M2-Del) yielded a non-functional protein with normal plasma membrane localization. Replacement of the motif in M1-Del with six alanines (M1-Ala) significantly improved localization of the protein and partially restored function. Conversely, replacement of the motif in M2-Del with six alanines (M2-Ala) did not reverse the phenotype and susceptibility to antifungal substrates of Cdr1p was unchanged. Together, the M1 and M2 motifs contribute to the functional asymmetry of NBDs and are important for maturation of Cdr1p and ATP catalysis, respectively.
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Manpreet Kaur
authors.initials: MK
authors.lastname: Rawal
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Atanu
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Abdul Haseeb
authors.initials: AH
authors.lastname: Shah
authors.affiliation: School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Mohammad Firoz
authors.initials: MF
authors.lastname: Khan
authors.affiliation: School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Sobhan
authors.initials: S
authors.lastname: Sen
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Ajay Kumar
authors.initials: AK
authors.lastname: Saxena
authors.affiliation: The Sir John Walsh Research Institute, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Monk
authors.affiliation: The Sir John Walsh Research Institute, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Cannon
authors.affiliation: School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Bhatnagar
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Alok Kumar
authors.initials: AK
authors.lastname: Mondal
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Rajendra
authors.initials: R
authors.lastname: Prasad
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000409:Alanine / Q000235:genetics; D020816:Amino Acid Motifs; D000935:Antifungal Agents; D001665:Binding Sites; D002176:Candida albicans / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D025141:Drug Resistance, Fungal; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D017510:Protein Folding
chemical_list: D000935:Antifungal Agents; C094693:CDR1 protein, Candida albicans; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D000255:Adenosine Triphosphate; D000409:Alanine