Table 2.

Carbonic anhydrases and C_i conversion system with putative CA activity in C. reinhardtii.

Location	Protein	CA Class	Activity	Physiological Role **	Regulation of Gene Expression		Acclimation State
					Low CO2	CIA5
Periplasmic space	CAH1	α	+	Supply Ci for uptake	+	+ (via LCR1)	L-, VL-cells
	CAH2	α	+	Supply Ci for uptake	−	−	H-cells
Periplasmic space or plasma membrane	CAH7	β	+	n/d	−	−	n/o
	CAH8	β	+	n/d	−	+	n/o
Cytosol	CAH9	β	n/d	n/d	−	+	n/o
Mitochondria	CAH4	β	+	Conversion CO2 into HCO3−	+	+	L-, VL-cells
	CAH5	β	+	Conversion CO2 into HCO3−	+	+	L-, VL-cells
	CAG1	γ	n/d	Conversion CO2 into HCO3−	−	n/d	n/o
	CAG2	γ	n/d	Conversion CO2 into HCO3−	−	n/d	n/o
	CAG3	γ	−	Conversion CO2 into HCO3−	−	n/d	n/o
Chloroplast stroma	LCIB *	θ	−	CO2 leakage prevention	+	+	H-, L-, VL-cells
	LCIC *	θ	−	CO2 leakage prevention	+	+	H-, L-, VL-cells
Thylakoid lumen	CAH3	α	+	CO2 generation for Rubisco	±	n/o	H, L-, VL-cells
Flagella	CAH6	β	+	Ci sensing	−	−	n/o

Components with confirmed or proposed involvement in the CCM are shown in bold. * Proteins LCIB and LCIC form a complex that functions as the C_i conversion system in the chloroplast stroma. ** known or predicted. n/d—no data. n/o—not obviously.