Protein folding and membrane localisation. Fractions obtained during the large scale membrane preparation from P. pastoris clones expressing moderate (HsAQP8:100:2) or high (HsAQP8:1000:1) levels of recombinant HsAQP8 analysed by immunoblotting. Lane 1-5: HsAQP8:100:2 fractions (crude cell extract (1), 1400 g pellet (2), 1400 g supernatant (3), 150 000 g supernatant (4) and membrane fraction (5)). Lane 6-10: HsAQP8:1000:1 fractions (crude cell extract (6), 1400 g pellet (7), 1400 g supernatant (8), 150 000 g supernatant (9), membrane fraction (10)). All fractions recovered were, prior to SDS-PAGE, diluted to a normalised volume corresponding to 270 mL/fraction whereof the same volume for each fraction was loaded on the gel. The protein folding and membrane localisation do not seem to be compromised by increased protein expression.